triple concaves and small waves

i have heard different theories on bottom contours for modern fish and other small summer wave boards. my question is for weak and mushy waves what kind of bottom contour do i want on a mod fish board? i have been told different though that it doesnt matter and the best bottom is perfectly flat. i have a 6’2" X 18" X 2 5/8" squash tail with a flat bottom and a slight vee in the lat 1/4. it dogs on speed in small waves. so i always thought single to double off the tail was best for drive and speed. can anyone help me out?