no matter what shape of heat-sink you use, below is my experience:
if the area(L*W) of heat-sink is doubled on that the strips or PCB board, then it should be workable;

First of all, I have to say great upgrade, mix 660nm is what am looking for; and here are some questions after viewing the video: 1, Are they OSRAM Oslon SSL 150, am going to DIY a similar QB by myself, so I want to know; 2, can PPFD test report be shared? seems only test at 3FT mounting height, its...

In my experience, for 480w QB, a bigger heat-sink size 600*600mm as a whole piece,
is much better than 4 pcs single small heat-sink pin together