From my own research, Sulcattas grow pretty fast. They'd outgrow a healthy indoor environment within two years. They're simply not good indoor pets. They are powerful diggers and will dig through walls if necessary.

I believe Russian torts stay relatively small. And the various box turtles (which are actually torts) also stay small and would probably be much more suitable to an indoor enclosure.

As for what to feed them...figure out which species best fit an apt life first...then read up on what they need. There is at least one or two retailers out there that sell fresh greens specifically designed for various tort species. I have to find old business cards from herp shows though...can't find the links right now.