Advice on COB - 4x4 grow

I have terrible luck building lights,but please tell me anyway in case I change my mind!!!

@CobKits I've just realized that since my first message, when I was aiming to buy/build clu1212, I've been looking at your website and prices. What a coincidence to have you here. If I may, I've just started a direct conversation with you, since I've some small doubts (potentiometer, wires needed) and might be of our mutual interest.