Don't take my word for it, but I would buy:
-1 half sheet of 1/4 plywood (4x4') + a few strips of lumber (one 8' 2x4 cut in half, etc) to reinforce the panel from flexing. Maybe some paint to seal it from moisture.
-Some eye hooks and ratcheting straps to hang & raise/lower it. Screw them into the boards.
- A cheap\free extension cord to strip for wiring, or a roll of lamp wire. Also some extra electrical odds and ends, like switches/wire nuts/crimps/plug end/etc. Various screws..
- 5x 10 packs of cheap (they were $5-6 for 10 pks at some point before supply chain issues, probably double price now?) Chinese e27/26 lamp base sockets from ebay ( the plastic white ones with fake spray painted copper paint on the terminals, and not UL listed, but good enough for lower wattage LED bulbs to screw into)
-13x 4 packs of 100 watt equivalent (13-15.5 actual watts per bulb usually) household LED bulbs from walmart. A mix of daylight and warm white. $8-11 per box depending on the spectrum, more for the daylights.
Then, I would spread out the base sockets in rows, making them equal distances from each other, and attach them to the bottom of the plywood panel. Probably 48 of them. I would wire the sockets up in parallel, and make it so I could switch off some of the rows for half power/full power with the flip of a switch.
Then, screw in 48 of household LED bulbs into the base sockets.
I would be happy I spent less than $200 on a true 650-750 watt LED light fixture, and use the money I saved on other equipment, like a chiller or automated c02 controller or something. I would be humble about it though, and not dog on the guys that spent way more for their fancy looking fixtures of the same wattage that the LEDS can't even be replaced and run 50% brightness after 5-10 years, lol.
Last but not least, I would train a perfectly flat canopy in a scrog net, filling the 5x5 tent wall to wall with bud sites, and hit around 1.5 grams per watt (2 lb + easy) at harvest.
Maybe sell a lb and buy a new commercial fixture, but why when I could build 4 more screw in LED fixtures for the price of 1?
Edit: 1x fire extinguisher