I am guessing it's a "Passive" heatsink? What type of 'heatsink"? Dimensions I mean.
I use up to 5 Vero 29 Gen 7's on 5.88x36" heatsinks from "Heatsink USA". I keep some kind of fan blowing in their direction and I never have a problem. I run 2 in "parallel" then pair them in series to match what driver I decide to use. Cuts my mA in 1/2 so more efficient and cooler. I run 8 Vero's off a Meanwell HLG 240 1400mA Each Vero gets 700mA for example. HLG 240 at 2100mA gets 6 at 1050mA each. You an get 2500mA from the HLG 240A(non dimmable)
You can get 312 watts pushing 3 Vero's. 104 watts each. But watts aren't what we are after. It's the PAR value. lol