There are plenty of quality Led Companies out there now. HLG, Mammoth, Medicgrow, Highgrove... the list goes on. I'm using a grow light science 640 and have almost a year on it with zero issue.
You CAN flower a 4x4 with 320w, it's just not optimal. Canucks latest video from his 3x3 flowered with a 240w light. I was pretty surprised to see his results.
I'm running a different light in my 4x4, but using using a temperature and humidity controller with an exhaust fan and humidifier you should be able to dial in your environment.
Hoping to change my username. When I first signed up my account was cancelled after a couple days without any explanation. Now that my new account is clearly not a fake and hasn't been cancelled I'd like to try and get my old username back.
"Top Bin Samsung and Ledestar Diodes"
https://www.ledgrowlightsdepot.com/products/grow-light-science-progrow-640?variant=40065906868266&msclkid=32ac15529d5a1feb9aec765bac942f22
I have a short run light that I built myself. Unfortunately with PLC not selling their strips anymore I need to buy something commercial and keep the diy light in my 2x4 for veg and the occasional auto run.