hey mate, i can help you out since im electrician, and im off until sunday, but i def recommend asking them first, because its not only buying leds and drivers, its also about mounting them somehow, so buying metal frame or making your own, from what ive seen prices are good, but they didnt have any in stock when i looked today, only those experimental, and the one suitable for you: https://growopz.com/products/300w-bridgelux-eb3-4000k-fixture-cpt-only is couple of cm too long for your box… as i understood, they make their own fixures, so see with them if they can make you one or tell you when will they have in stock, but if youll go diy route ill sure try to help as much as i can (driver selection, wiring diagram, some tips on frame building)…
also, check out this thread: Source code: C++ Temperature Conversion and Vapor Pressure Deficit (VPD) 🛠
there is a chart with recommended temp and humidity, and explanation why…
and here: GitHub - plant-og/vpd: JavaScript Vapour Pressure Deficit
you can download a web page (just click green clone or download button on right, download file, extract from .rar, and open index.html), where you can choose what grow phase youre in, and youll find recommended values in green for optimal plant grow…
btw @anon98152597 is there some thread where i can see your grow? 
im interested in your light, how big area you use and what leds, how is it going for you? edit: nvm, i creeped your profile page and found it!