Adding heat supplies and cold air returns to basement

RAYCC3

I am currently finishing my basement. I have a bi-level home and i am approx. 3 1/2 feet below grade. I have added 3 heat supplies off the main trunk to my family room, 1 for each of the 2 bedrooms, and 1 for the bathroom for a total of 6 supplies. I have added 3 4x10x6 cold air returns off the main cold air trunk with 1 in the family room and 1 in each of the two bedrooms. My question is do I have to much heat for the 960 total sq ft of the basement with not enough returns? Any help would be greatly appreciated. Thanks.