A 10 gallon can be split 3 times. No flaring all day is NOT stressful. I find it more stressful to visually seperate the fish. Yes bettas fight but they are still social.
Freeze dried blood worms will inflate inside your fish's digestive system and should only be used in moderation. I would switch to frozen blood worms.
Who am I? Well I am a Junior Member of the International Betta Congress and a breeder of white HMPKs, red dragon HMPKs, black/red dragon HMPKs, metallic multi HMPKs, blue masked HMPKs, and now multi color HMs. Soon to add black HMs. I will be showing in New Breeder class in fall of 2012.