My bettas usually get 6 or 7 Hikari pellets at night, but if I can (ie if I get time) I spread the feeding out and give them three or four morning and night. I feed nothing on Saturday, I give them peas occasionally, and also the odd bit of frozen bloodworm. On Tuesday, they don't get hikari pellets, they get some really cheap stuff from the LFS. I use the stuff as tadpole food because it's vegetable based. The pellets are about the same size as hikari pellets, I feed three to each betta in the belief the fibre content clears them out as well as a pea and they find it much more palatable (most of mine only take peas on Sunday morning when they are really hungry, and some won't eat them even then. They wolf the cheap pellets.)
Overfeeding doesn't automatically cause SBD. When I started conditioning for spawning and I wasn't quite sure how to go about it, I fed both male and female about eighteen hikari pellets each. I did that twice, once in the morning and once at night. They got a bit blocked up but some peas worked. So they will eat far more than their digestion can cope with, definitely, but about ten pellets three times a day seems to work to condition.