My next step was in adding a needle valve to the bottom input. This works fine...but there has to be a way to bleed off excess pressure so a Y or T fitting to split the lines was involved. The issue here was no matter what I tried, the water would always flow entirely out the opposite side of the T., leaving my deplheg starved for water. Evidently, this has something to do with Bernoulli's law...and the problem is the volume of the dephleg..is much greater/larger than the hose feeding it. This introduces a constant back pressure that has to be overcome. I read some where the way to do it was to reverse the water flow, (ie., make the bottom the output) and make sure the split in the line came above the water line. I read elsewhere..to make sure it was done below the water level of the delph.
As it was..I tried every possible combination of possiblities I could think off until I was exhausted. None really worked. I even sealed up the other end of the T, and made a tiny pin hole it...trying to introduce some backpressure into the system. It didn't change the behavior. The dephleg was still starved..and the water flow erratic. EVEN with the valve wide open. So, I pinched the hose shut...it "still" fought it's way past...although that did eventually cause some water to go into the dephleg. I recognized this could work to solve this issue by simply using a valve (and/or manifold) for the output/release to keep enough back pressure in the line to make it all work — this seems to be the method most people use..whether they use Y with 2 valves, or a manifold with 2 valves off the product condenser. I tested it by placing a PVC valve on the output and balancing that with the overall water flow so that the delph would function properly. While it did work to some degree...it also meant having to balance the flow with the pressure...and fiddle with 2 valves. It was still rather precarious and I was determined to get rid of any "Y" or T line feeding the dephleg. This just had to go. It was far to fiddly and nothing "really" worked or gave the very fine control I'm gonna need.
After looking at some images, reading, etc...the next thing I tried was moding my dephleg head. I added another input nipple to it..just below the top one..on the back side..to use as input from the liebig/product condenser. And I put the needle valve on the bottom...now used to control "output" (reversing flow). And I put a drain/overflow tube onto the original top/left output nipple. This...worked like a charm! I can feed my deplh from the liebig, without having to worry about backpressure/flow issues. If the rate of flow in is more than it is out..is simply drains off the top maintaining a full delph. Moving the needle vavles ..even in very small increments, was working great. And going even from full open, to full closed..and back...didn't screw up the water flow (ie., cause a vacum, etc). I've only tested this with water...but so far...it seems to work really well and allows for very fine adjustment.
. Bout as far as I got in the Wile E Coyote school of physics.
While the water flow works well in so far as being able to control it....not being able to control the flow from the water source means...that while I can heat up the water in teh bottom of the deplegm by closing the valve...it just keeps pumping cooler water through the top of the dephlegm and the water never got over 150F...and that was with running the liebig about as far down as I could (ie., hot). Trying to run cold water off the tap into it from a T didn't work either. There was a sweet spot with flow...where the amount coming in, was equal to the amount going out. But, it was too much cooling. I definitely need pre-heated water, and control over the flow of it going in. 
