Bridgelux EB gen 2. Eighteen strips will just fit, and a 200 watt adjustable driver will give any light level you want from clone up to kill-a-plant. No heatsinks needed, can be turned down and run two inches from tops for maximum headroom if needed, and the even coverage from a 20"x23" panel can't be beat.
Decided in the end to get a 150w HLG Quantum Board, I've heard many good things about them and it should be perfect for my tent as it recommends 60x60 flowering footprint for this light