Roots excel is the best root booster on the market period. At least thats what I think. About the drip clean, looks to me you are still in veg and the plants are not that old so I really dont think that it will cause a prob for you GOO. They have not had that much time to develop too much salt buildup, and you mentioned that you run your nutes at half. I also run my nutes alot lower than recommended with great results and no deficiencies. There used to be a chart on the web( I think it was made by heath robinson ) that would show what levels of nutrients that the marijuanna plant would grow healthy without deficiencies, it was ridiculously low. Wish I could find it again. Anyways, do what you mentioned and start out low and monitor them for burning, I really think you will be alright but just watch'em.