Hey, just reading your grow journal. Looked good but some of the problems you had were some of my previous mistakes. The hermies with seeds is probably due to the 24 hour lighting in veg. It really stresses the plants, and plants can only absorb so much light in a day. You will save money on power, stress the plants less, and they really won't grow any slower. I tried the 24 hour light last grow and am back to 18/6 on this one, no difference in growth speed.
I love rockwool too, its my preferred substrate. I used to use cubes and slabs but its too expensive. Try the granular rockwool, its way cheaper, you just need containers to hold it. It comes in 2 kinds, absorbent and repellant, mix it 50/50. Its $64 for a 45lb bag, and 45lb of rockwool is a lot more than 45lb of soil because of its light weight, the rockwool is 13.5cu ft. The granular will perform the same as the cubes but for half the cost.