Good luck. It's always a crap shoot with the betta, it seems. Just depends on the personality of the fish, how much space you've got, hiding spaces, the phase of the moon, etc. Hope the bigger tank(s) works out for you!
My betta kept my apple snail hostage in the corner of the 5 gal. tank. He don't wanna share his space with nobody. Darn shame, too, since I wanted to add african dwarf frogs to the tank with him. He's a solitary dude. He even flares at the picture of another betta on his betta food container.
Keep us posted!