In the future please don't revive old threads- best to make a new one.
For pellets, I always recommend 2-3 pellets per meal, twice a day. If your betta has a tendency to bloat easily, then 1-2 pellets per meal twice a day.
Bettas can be very picky with food- no two bettas of mine like the same things, so I have quite a selection of food in order to give them all a variety. All of mine also eat different amounts- my old guy who is curved down quite a bit from age, which makes him have a pot belly gets only 4 pellets a day (2 each meal), while another, say my girl Aanya who is about 5 months of age eats 6-7 pellets total a day. (Only counting pellets, but they are fed other foods as well.)
Flakes may cloud up the water, but betta specific flakes are fine to feed them- make sure that fish/meat meal is the first ingredient and the crude fat % is higher then 42%.. feed only a few flakes at a time, a couple times a day. They won't cause bloating or constipation, as some people believe.
Go ahead and try the 3/3 meal plan for him and see how he does- their stomachs can and do expand after eating, so keep that in mind. By the time the next meal comes up they shouldn't have a bloated looking belly anymore.. if that is the case then I would slowly go down in the amount fed to where he can digest it easily.. each one is different, like us, with their metabolism- but unlike us, they don't get fat.