I made the mistake of planting my HC big the 1st time, the 2nd time I really changed it up and have WAAY better growth. I did not do a DSM though, the HC was grown submersed and I kept it that way. In my sig you can see how small my clumps were and how they are growing in. For me a more pwerful light would be very beneficial. Also, I saw you left the rock wool on the roots, use tweezers and pull them through the roots to dislodge the rockwool and plant without it, it tends to cause more harm than good.