I would go with the 20 gallon meathod. I have used it before. First like 5 to 8 weeks for a 2 dozen or so fry, power feed and do w/c @ 50% everyday. Then move them to something bigger like a 40 breeder,following the same w/c @50% everyday. And slow down there feeding a little.... they'll be of selling size in 3ish months. I had jags that were seelling size in 10 weeks. I know that dmd allready suggested this, but I though I would reiterate, and provid some more detail... there are trace elements in fresh water that's added daily that helps the fry grow much faster... I am useing a 125 to grow out some jag fry now (leaving them with there parents) and the w/c's are costing me a lot of money, 70ish gallons a day. And that dosent include my regular weekly w/c for all my othe tanks. Good luck with whatever meathod you use.