More info about continuous columns?

[rectifier]

Does anyone know a site that has more info on continuous columns?

I just had a stroke of luck, and found a decent bit of scrap 1 1/2 and 2" copper at work in the recycle pile today, with fittings. Also some battered but working thermometers and a big bucket of copper swarf, to use for packing.

It's filthy, so is going into a fuel still, and I plan to make it a continuous one - because batch runs of fuel isn't too efficient, and the foreshots/heads problems with continuous stills obviously don't happen with fuel.

So, I've read the homedistiller.org continuous section - not much info.
My issue is that I have a goodly amount of 1 1/2, but only about enough 2" to make a regular column. I also have a piece of 2" with a center feed as required for a continuous column brazed into the side... lucky coincidence???

So anyways, either my lower half ("stripping") or upper half ("rectifying") column will have to be 1 1/2" - which will choke my column more? More vapor will be flowing through the upper half, being above the feed... but more liquid will be dripping through the bottom half.

And, how should I head this thing off... I need reflux, but a small amount compared to a drinking still. I'm only aiming for 80-90%. I figure I'll do a hybrid offset/elliptical plate design, which would allow for a large range of reflux ratios, and allow "no reflux" running.