Sorry been busy lately and came late to the party…
for growth rate, my old girl went straight into a 200G from the get go at 1” and grew to easily 12” in the first year…
as for foods, i agree training them from a young age to accept new foods is best, i just cut up small pieces of mussels, scallops or whatever other frozen foods i wanted to feed her and used tong to train feed her. This way she learned to associate whatever was at the end of the tongs as food…
As for tank size, there is as always a lot of debate around it, but the general consensus is that a 5’ 125G would be the bare minimum, although personally i think a 180G would be a better choice for an adult puffer…
-edit-
regarding moving the fish, i think its easier to have one tank setup than to be constantly moving the fish throughout its life but thats just me, use your best judgement and keep an eye on growth rate as they can get stunted pretty easily if not careful due to their growth rate and in a smaller tank you may not notice they slowed down as much…