It's a copy of the P1SS, so try
http://www.sump4.com/rebreather/ to ess roughly what I've done. There are some mods to make right now, I'm not too happy with the push-pull operation, and I'd rather have a loop so I know that all the gas is getting scrubbed. Some CO2 I'm ok with, but not if the scrubber's not doing it's job properly too. With the current leaky situation, it's better I think that way.
The only difference at the moment is the reg I've used has an OC reg on it, and 6" hose and small gauge, just because I don't like those buddy things. The OC reg is a sort of bail-out. As I see it, if I'm getting a CO2 hit (which is the most likely way it's going to go tits up if you ask me) then I want as many regs available as possible. Preferably with high O2 content. It also means that when I'm using the unit for deco I can carry my 6s as per usual using the RB basically to save O2 and keep me warm, and if there's a problem I deco out as per normal. It could be fun mounting the twins, a couple of stages and the RB, but then it could be kinda fun too. All I need now is a scooter...