Hmm. This is a tough one. He's been doing well for a while now, hasn't he? I remember the food-related bloating problem. Just to be clear, the bloating does go down after he digests, right? I think part of how well he can digest food of any kind may depend on his genetics.
If he's not bloated other than right after eating, then I would try feeding him every other day. This is actually how I've started to feed my bettas because they seemed to be developing health problems related to possibly overeating.