My guess is it's your ballast. The reason I think this is because your MH bulb dims while running and your ballast wont run the HPS. Now the Lumateks do flicker a little bit especially the older ones. So if it's flickering it may be the bulb but if it's dimming that doesnt sound right. Also how...
You can drop your cuts that are in rockwool right in a pot of soil. Rockwool sucks IMO, especially if you are new to indoor growing, just stay away from hydro and go soil. You'll be much happier you did.
It's super close man. You're trichs are obviously still clear so now you have a choice to make. Most growers opt to pick when trichs are 50% amber and 50% hazy. More hazy gives you a slightly more head high and more amber gives you a slightly more body high. Ahh the fun of growing. Keep it up...