1. Those are amazing roots for only 7 days. I agree the heating mat speeds things up, but 7 days is unreal.
2. Even at a humidity of 45%, my clones (in rockwool) wilt if I don't use a dome, and I only allow ambient light until I see roots.
3. I like the size of those clones. BIG! Do you find taking bigger clones will you a head start on rapid veg growth?
4. 1ec / 500ppm seems high for clones, but it seems to be working for you. I use about 1/2 that. I usually use clonex solution or GH bloom nutes and I can't tell a difference. In the video, you said you are using advanced nutrients, G,M,B, but are you using EQUAL parts of these?
5. When you say 3 part, you're referring to the "jungle juice" 3 part, is that correct?
6. I agree more plants per light will always yield more than one big plant. I wish I had the luxury of higher plant count. What I have noticed, is I can always get a lb per plant, using the 5.8 gallon superoots air pot. I've run the next size up (12 gallons), which uses a LOT more media, and it does NOT increase my yield. I believe it is important to transplant often to build a big root mass (which I see you are doing).
Great video, cult. There is more info in this video, than one would find in hundreds of threads around here!