wont be any fish in the tank. If anything living is in there it'd be pond snails. I'd grow out a big colony as food for the puffers.
you should grow out ghost shrimp too. Mine don't eat my RCS tho...
How many puffers are you going to put in the big tank, that should be a LOT of money if they cost as much as they do here. Why not breed them in the 10 and keep the babies to stock the 72 with. (after you've grown out a lot of plants)