imo two CMH 315s would be too might light in a 2x4, almost 80 watts per square foot! altho i guess for HID lighting that might be normal
a mars hydro TS1000 is 150 watts for $129, so around 1 dollar per watt, and is nearly as efficient as quantum boards or other PCB options which generally cost $2 per watt or even more, so 2x TS1000 in a 2x4 would be great.
Migro on youtube runs tests on all the most popular LED brands so its worth checking his channel out to see if he’s tested any particular light you’re interested in
personally i’d order components directly from china and assemble my own light but it’s a little more difficult and requires a bit more effort