Well around 1/4 of a 4'x4'. Total would be around 400 led watts @ 56%, for the ppfd of 650-700 over a 4'x4'.
Distance will probably be closer than before. 12-14" over the canopy covers a 2'x2' well with unreflected 115° Cree cobs. Or 18-21" high with 90° reflectors.
My canopy varies too, so a lux meter is a good investment for seeing what canopy&light distribution works best. I like larger plants more center to get more light&penetration and shorter ones more at the edges getting the most out of the reflected light. The opposite with larger plants on the rim and smaller in the center would utilize light best I think.
Cheap tool to keep handy and the cxb 3500k 80cri lumen to par conversion is .0143 ( 10,000 lux is around 143 par).