Need Help with DIY Led Build

Alright so here it is. I have been researching Leds and I am ready to make the switch. This is all new to me so I appreciate any constructive feedback. I have a 4x4 tent and was thinking of fabricating a veg and bloom panel with #20 Cree-cxa2530's cobs #10-4,000k(42v, 3680lm@800ma, max drive current 1600ma), and #10-3,000k(37v, 3609lm @800ma, max drive current 1600ma). #4 36 inch (4.850) heat sinks with 5 cobs per heatsink and 4 12v fans on the top panel for active cooling. I have read that you don't want to run them at full strength so I am thinking of purchasing a dimmable driver. So my questions are: First of all. Am I on the right track with this configuration? How I determine what Size Drivers I would need and how many? How do I calculate efficiency? I would like the best efficiency I can get with this particular set up. I realize there are more efficient cobs on the market but this is what I can afford at the moment.