I ended up re-doing mine with smaller holes which worked better. I think i settled on 1/32 bit - really tiny. 1 1/2 inch PVC in a T of ~16 inches on each side. I have it sitting just above water level (bottom of PVC is at water level). Two rows of holes. Each rows holes were probably separated by about 2 inches, with the rows staggered (so high row would be at 0", 2", 4", etc, and low row would be a at 1", 3", 5", etc.). You may have more holes than necessary, but I suspect your bigger problem is not blocking some of the other returns. I suspect tinkering with that as you suggest will help. You'll get circulation either way, whether you return via typical jets or return via the fountain. I know Dave goes for 20 feet of height, but my pool is a lot smaller and that isn't really practical for me. I only go for about 10 feet of height but have gotten great cooling action from it.