First off, welcome! Second off, don't tell many people what you are doing!!!! Unless you trust them with your life, keep it quiet.

Okay, so running heating elements is okay. That one you listed just screws on.....it is great! I have one 1500w and also use my stove. The stove is the control, and the 1500w stays on full time.

A motor speed controller is what you are looking for to control the elements. I'd only use one really.....stripping you can run two at full power (depending on your setup and cooling), and for spirit run, you can control it with this. HEAT SINK THE SOB! I blew one out because I didn't know I needed to heat sink the back.

Besides that, it's a simple device. A large pot with sealed lid and pipe fittings. Seal with clamps and flour paste...no plastic.

What cooling system do you plan? Leibigs are really easy to make, and can scale up to a large size (or if you like soldering, a shotgun is a more complicated leibig), plus you can take it all apart and store it hidden!

and you are correct....once you actually DO it, things will fall into place, and make sense. That is always my troubles. I get scared of what I'm doing, until i actually do it....and poof, it get easy from there!!