UPDATE:
Ok boys and girls. I spent all day Sat building a new head/dephlegmator reusing my internals and various parts from the old one, and adding a few new ones. I disassembled the shotgun, and cut it down to 2". (2 x 2). I made the valve on the bottom "input" now instead of output. And I put a drain/output at the very top...using a "T"...and NPT threaded therm so I can monitor the exit water temp. I added a special high-temp hose for the output knowing that the water was going to get hotter than my plastic ones could take.
I used all 4 plates and ran 3 gals of mixed water/heads/feints that came out to about 10% ...using it to clean for cleaning run. I ran a "T" from the sink flowing cold water (the one with ball valves on each side), and adjusted water for max flow to both the depghlegm input (controlled by needle valve) and the liebig. After that, my plan was simply to use the needle valve for controlling flow to depghlegm and the ball valve on the other side to control water to liebig as needed. That was the plan anyway. Once the vapor came up, to about 170F-..drips started coming out. I turned the heat down slightly (to med-hi) and increased the flow to the water system at the sink. Now, I'm flowing full out, valve wide open, and lots of flow. It was still dripping, but only about 1 drop every 3 sec or so. The vapor temp settled at 174F. At that point, I had a couple leaks that I patched with paste/dough.
After adjusting the flow up, heat down a little, I was able to get it to stabilize under full reflux and I left it for about 20 mins. Still at 174F. Looking good so far...but having to flow so much water through the dephleg to get full reflux had me a little concerned at that point. Alas, I started to reduce the flow via the needle valve...and as I did..I monitored the temp on the water temp on the output. I fiddle back and for with this for a long time. It responded fairly quickly in regards to temp changes. If you turned the valve off...the temp would quickly rise. If you opened it up..the exiting water temp would quickly fall. But, getting to stabilize was bit more tricky. It seemed it always wanted to either rise or fall. Making the changes smaller just made that happen slower.
A long story short...after many mins of fiddling...I found that a very small amount of flow was needed through the dephlegm. (my needle valve goes from 1-10, three times around...each time revealing a different colored thread/ring. I started all the way out..and ended up on the first ring at 5. When the water temp finally got up to 150-160 it started to drip. I was looking for 170-180F. I finally got sort of a fast dribble at 170. And at 180F..it looked about right (ie., almost a stream ..but not quite). When distillate finally emerged from the parrot it registered 85%. I fiddle some more with the water, etc. tweaking for flow and just testing it. It was apparent that even with the 2 incher dephlegm..it didn't take much flow at all. So, I upped the heat just a bit...to drive it a little harder (as per suggestions here). Soon, the vapor temp was up to 190!! I opened the valve up...and the dephegm responded immediately...stopping the flow. The water temp on the exit of the dephlegm..dropped smoothly but fairly quickly. The vapor temp dropped...but only to about 185F...I looked at the parrot...it was showing 80% in the parrot (ie., it was dropping from 85%). At first I thought something was wrong...but then quickly realized, Its just running out of alc. (there's only so much in 3 gals of 10%). And it was getting tricky to stabilize....another sign. I closed the valve at that point and took off the tails.
I collected 425ml of distillate total. Given it takes about 100-110ml to fill my parrot before it starts coming out...it was impossible to get any sort of reading on it from the very beginning and through transitions, etc. But, what I observed was, by the time it was coming out of the parrot, it was about 85%. It held there only for a bit, then started dropping steadily...down to 85%, then faster down to 80%...then towards the end quickly to 70%. From there, I just closed the valve and flushed out about 120ml that measured 20%. As to the distillate itself...the first that came out was nasty! Strong smelling heads, with a hint of flux (yum). I didn't really taste anything cause it was full of flux.
SO: In the end...comparing this to my run on wash using the old one using the same setup (water T at faucet control flow via the ball valves on the T), I think I was using about the same amount of flow/water. It was just much easier to control using the needle valve, as opposed to the balancing act using the mini ball valves on the faucet T. I think the shorter dephelgm responds much quicker to input changes. I'm not sure whether this makes it harder to stabilize or not..given I didn't monitor temps on my other rig. I'm gonna leave that question for later, given the small alc in the run...also made things less than stable (ie., temps constantly rising, requiring more cooling, etc). So, there's a lot of factors that play into that. The therm on the output...was good info and monitoring it confirmed what I suspected. Somewhere around 180F is where you want it to be. Taking that into consideration...the obvious is...the larger your dephleg is...the longer it will take to heat up, and cool. Whether than translates into making it more stable..is another question — it may respond more slowly, but it's still going to rise, fall...etc. I found the most effective way to use mine was to make a large adjustment..to get it into the general temp range I want (like turn it off till it reaches 170), and then crack it open just a bit to slow temp rise in that general area...and see where it ends up. A few minor tweaks from there...and I was on 182F. It was rising very slowly, given the temp/vapor temp rise.
The only thing that concerns me at this point..was at the very beginning when it didn't provide total reflux. That was under full boil...and while I had continual flow through the dephlegm (small stream) it wasn't enough — although there was more flow possible through the faucet itself. That is to remember that I'm not using heated water off the liebig...but cold tap water. It's yet to be seen if I've gone "too" far. But, I think this is much closer off the bat than the previous attempts were, and everything else seems to be working in so far as the water control, etc. The other thing related to this was...at some point over 200F vapor temp, I tried to re-stabilize it...and knock the vapor temp back down to 170s-180. It would only go as far as 185F at that point just using the valve all the way open — again possibly pointing to not quite enough knock down when it's full-out.
I was hoping to see 90% or better off the bat with the 4 plates though ..given that would have at least been an encouraging sign everything was on the right track. It may have well been up in that range when it first was dripping off. But, trying to get stream out of it...playing with water flow, etc...the vapor temp quickly shot up and abv was falling from there. Perhaps more alc in the pot will help with that (we shall see). But, I'm pretty much convinced at this point...that trying to do spirit run on 5 gals of wash/mash is pretty pointless. You need volume for that. That's it for now. Got a few leaks to fix up.