one thing to consider is an existing switch in the unit. if I had a switch I would connect it with a pair of wires to the pinouts labeled "Man" on the PCB. This allows you to manually turn on the white LED and use the fixture as a work light.
None of the units i purchased had this switch -- excepting the harbor freight units I purchased last year, but I ran the extra pair into the junction box anyway. at some point I'll find some cheap waterproof switches and wire this up in the switchless units I now have.
the harbor freight units 'might' work, but last year's heat sink was too large and I used the boxes for 5050 "cheapo" floods.