Nice to see people are still building lights
I would recommend choosing to either do a full strip build or a full board build.
Buying boards with heatsinks from HLG, Atreum, Kingbrite etc. is the easiest path but strips will give you a more uniform light source that can also be closer to the canopy.
With the setup you've drawn, you'll have both hot spots and cold spots and you'll have to have the boards further away from the canopy than the strips and the strips will shade out some of the light from the boards.
LM301H and LM301H Evo are basically just product marketing for the horticulture market, they're not actually any different from LM301B and the bin batch you get has way more to say than B, H, or H Evo.
I highly recommend using the 2' Samsung H-inFlux strips, they're sturdy and easy to build with. You can get them from Digikey, Arrow etc.
Series, parallel, or mixed doesn't really matter, I usually let the ideal driver for the light I'm building decide which route I take.
A single driver will be a tad too weak for each of the builds maxing at about 600w each, the board build should be 750-800w, stip build depends on the strips used
Building bigger lights is also more complicated and more prone to making wiring mistakes and then having to backtrack a lot of connections.
Having everything set up as per your drawing would mean a whole lot of wiring, and you'd end up with a single HUGE lamp that'll be a pain to work with when growing.
Multiple lamps makes framework and wiring much easier, waaaaaay neater, and the wiring will be a whole lot shorter (and voltage drop is no joke
).
I'd recommend using the Mean Well HLG series drivers and do parallel wiring, it's the easiest if it's the first light you're building.
At first glance I'd say building 6x 250w lights, 2 for each row, would be sufficient but 6x 330w lights would absolutely slay
I can easily help you with complete suggestions and schematics if you answer a few questions:
How big are the 3 active grow areas respectively?
What's your materials budget and max wattage willingness?
Are you planning to have a switchbord/controlboard with drivers, dimmer, and timers?