That's great to hear you have access to nice machines! CPU heatsink works well.
If you go with HLG-185H-C1400, you can drive 4x CXB3590 or CXB3070. Slightly more light (with the similar input wattage) with CXB3590. It doesn't have enough voltage for 4x CXA3070, though.
From calculation based on data sheet, CXB3590 appear to be worth getting. But the PPFD measurement done by one person, CXB3070 seems to be not far behind from CXB3590 at the low current. So it's difficult to say the extra $13.50 is justifiable. There appear to be more choices of LED holders, reflectors, and pre-drilled heatsink with the smaller CXB3070.
If you go with HLG-185H-C1400, you can drive 4x CXB3590 or CXB3070. Slightly more light (with the similar input wattage) with CXB3590. It doesn't have enough voltage for 4x CXA3070, though.
From calculation based on data sheet, CXB3590 appear to be worth getting. But the PPFD measurement done by one person, CXB3070 seems to be not far behind from CXB3590 at the low current. So it's difficult to say the extra $13.50 is justifiable. There appear to be more choices of LED holders, reflectors, and pre-drilled heatsink with the smaller CXB3070.