You may still be learning, as I think I always will be, but it sure looks like you're doing pretty well! Waterfarm-style drip + scrog = big yields, from what I've seen. 2 x 400W in a square meter, really? Way to not skimp on the light!
I'll soon have access to a new flower room just a bit bigger than yours and I'm thinking of doing something similar, but with 300W-400W of COB LED. My first grow was with a dripper, then I switched to DWC bubblers for a couple, then Pro-mix mix ever since, but I want to try to scrog a couple of plants. Do you like the Canna nutes, or have any comments about them?