Nah, I decided to go the CXB3590 way
Holders or not, the mind is set*.
6x 3590
2x hlg-185H-C1400A
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total around 300W(50W/cob) with possible addition of another pair of 3590s in the future
I think it's a great setup for a start.
It will cost almost the same as a CMD 315W light but I'll have more versatility and lots of fun building it
*totally obvious question: which is the best way to fix the cob on the heatsink without using holders?