It shouldn’t take anywhere near 20 amps to light a 2’x4" and add a fan. If you plan on adding a/c and dehumidifier, maybe that would push it. I don’t have a par meter, so we would have to do some research and take some other people’s word for it. But I’m game.
When designing an led circuit, some things have to take priority over others. If you want the most light per watt, you run them soft and just add more leds to hit your target coverage. This runs build costs up though. So the alternative is to buy less leds and push them a little harder. You’ll get more light this way, but it will consume more power. There isn’t exactly a right or wrong way, it’s just deciding whether your build is going to target the best bang for your buck up front, or in the long run.
I’m thinking the textbook 1 cxb 3590 or citizen clu 048 per square foot would put you there, but I’d have to check on the outputs at different currents before I said for sure. You could probably run 6 vero 29’s a little harder, which is kind of their thing. I’m sure a strip build could be configured, but I’d have to look more into them as I’ve only done smaller ones. Probably the easiest would be something with quantum boards, but they are hard to catch in stock.
Soldering isn’t really required much anymore. But the fact that you can and have at least a little experience with electrical components will help. Let me do some digging around and I’ll post back.