I guess a lot of it does come down to what is an acceptable temperature, because those cree bulbs are hot as hell.
That is correct, the COB will not be destroyed by running on that heatsink and it will still grow pot. But the consequence may be that loses much of its advantage over HPS. You are also correct that thick fins have a better thermal conductivity, they move heat faster and further with a lower temperature gradient, but without sufficient surface area they cannot get rid of the heat. The surface area allows the heatsink to take advantage of the temp difference between itself and the surrounding air. So the best thing is a combination of thick base plate+ lots of surface area (or lots of air movement which accomplishes the same thing).
Running at 1.4A and Tj50C they are 34.5% efficient. Running at Tj 100C they are 31.4% efficient. That is 10% less light/W. So for each 53W module, if you spent less than 5W cooling it, you would see a worthwhile gain.
Regarding vF, based on the "typical" numbers from the vF curve in the PDF, you would need to run at .7A in order to fit 4 Vero 29s on the HLG-185H-C1400A. In practice you might be able to go a bit higher, especially if the Veros are running hot. If you hook up 4 Vero29s without dimming it first, the driver will go into "limping" mode. As soon as you go even slightly above 143-144V, current will drop off very steeply (less than 700mA). As a side note, these drivers are very impressive. They deliver the specs they promise, awesome efficiency, very competitive price, power factor corrected and you never know when dimming will come in handy.
It's all in the re-reading
Thanks for the props man, this community helps each other out in so many ways, we have a great group of LED growers here
