[Disclaimer: Although this worked for me, I do not recommend tampering or modifying a pressure cooker in any way. Modifying or removing safety devices on a pressure cooker can lead to explosion and possible injury. Blah, blah, blah...]
Pressure cooker: Pretty much any decent size pressure cooker (use AT LEAST a 1.5 gal unit) will work, although I wish I had gone with a much bigger unit (see below). If you are lucky, you might be able to unscrew one of the fittings on your pot, insert a tee junction, and run attach your valve to the pot this way (worked for brewman !;
see here). The fittings on my pot were too small, so I tapped a 1/8” NPT thread into the lid, and screwed in my valve to control the flow of steam. Works perfectly. I also added a 3 inch piece of 1/4" copper tubing to the valve (it has a built in 1/4" compression fitting) to attach the tubing. A 3/8" inch hose clamp would be a good idea – mine held without it…. until I kinked the silicone tubing and it blew the hose right off the pot!
Steam manifold: I bent 3/8" tubing around a small pot to form a loop. I sweated a T junction to complete the loop. I then drilled about eight 1/16" holes in the tubing with a drill to allow the steam to escape. The silicone tubing can be stretched over the end of the T junction, and mine was snug enough that it did not require a hose clamp. A small thumb clamp can be added to the hose if you want to stop the flow of steam at the manifold end (useful to prevent backflow when the steam flow is stopped at the pot).