Jerry @ Kingbrite was a good guy back in the days of COBs just coming on the scene, 4-5 years ago, but I don't know about the company today. Personally, if I was willing to risk buying from China, I'd go with the Meiju FOTOP 800 lm561c boards, 3 per 4x4 on an HLG 480. Buying in multiples of 6 saves on shipping.
However, I'd probably go with Samsung lm561c s6 3000k 42" strips, 6 per fixture, two fixtures per 4x4 if I was building right now. That's the cheapest, best spread, LED DIY option that comes with a warranty. And all the "enhanced spectrum" and UV and other bs is totally unnecessary until you have your grow perfectly dialed in, and even then it's arguably still a waste of money for the actual gains.
No matter what you do, do not buy the drivers from China. You won't get a warranty if you buy them there. Buy them local to you from Arrow or Digikey or similar.
As coreywebster said, always negotiate. Always.