I can't help you with plans but Bart's link is a good start.
I myself think 10 tubs is perfect for a small set up, and if you run it just right you can have a mom with pinks every week.
I buy my rats local I bought my females from one store and the males from another. I replace my own females with my own litters and I bring in new males every year to get fresh blood. Being that your breeding for food genetics is really minimal at best.
Being again that these are feeders its important to remove animals from the colony that don't meet your standards.
-Biting animals
-females with small litters
-cannibalism
Anytime I see any of the above the animal meets the chamber.
A CO2 chamber is easy to make yourself. All you need is a Rubbermaid tub that latches or seals so the animals can open it.
A length of Hose, and appropriate fittings for either end. A 20 pd tank with gas, and a regulator.
The regulator can be found at a garage sale in an old welding setup. There are CO2 specific regs and many people use CO2 with MIG welders...so keep your eyes peeled. Its also to find a new reg at either a welding supplier or anywhere that sells Keg setups for home use.
Once you get everything and start the setup, you note there is a proper method of freezing the animals.
-Gas
-Freeze
-Package
If you don't freeze them before packaging immediately after gassing, A rigamortis sets in and B if you vacuum seal them before freezing the will turn to goo when you thaw them...
Good Luck
-----
Jeremy Payne
JB Reptile
1.0 Snow "Kahl"
0.2 Triple Het Moonglow "Kahl"
0.1 Orange Tail Hypo Het Leopard
0.1 Double Het "Sharp" Snow
1.0 Ghost
0.1 Possible Super Hypo
0.1 DH Ghost
1.1 "Kahl" Albino
1.0 Hypomelenistic
1.3 Pastel Hypo
0.1 Suriname/Columbian cross
0.1 Anerthrystic
1.1 Morelia Clastolepis