I still havent built it yet. Its still all SGS-160 in there, hehe. Im leaving for Europe soon, and then Ill bring back all the small stuff that I need for the build. I figure from your comment, that it would be a good idea to just simply buy the extra cobs. Who knows, Id rather have them and regret that over not having them, and regret that. Thanks for taking your time to answer and also for sharing your experiences. Its greatly appreciated, especially by a lot of lurkers.How are your cobs laid out in that 3' x 4', 3-2-3? I wish and still may go with 9 at 1050MA for a total of 465 watts (3 HLG 120 1050's) but at 61% efficiency. If it's not to much trouble I would complete a run with what you have and the see what you like. It is a learning curve for sure...