I fed nutrient solution the entire grow successfully with sensi. The plants will take what they need out of it - just don't overdo it and keep and eye on how they react. That's why I prefer hydro - you can always monitor exactly how much your plants eat/drink.
I am currently using Sensi Grow and Bloom as well, I have been doing, Feed (wait 2 days) Water (wait 3 days) water (wait 2 days), repeat. When I feed (Sensi Grow for veg) I also add in B-52, and Voodoo Juice.