You could do 2 cobs per mars 300.
50v citizen cobs would give you 30 watts per cob.
Or you could go with Cree 72v which would put you at 40 per cob
You could do a full frame and ditch the mars too. Little more money but easier and better. Considering the cheap drivers in the mars hydro.
4 auto cobs would be the easiest. Fully adjustable and very efficient. Out of the box ready to hang and grow. Meanwell drivers, citizen cobs in a complete package.
Just started these under 2 cobs and last night added a third, next week I'll add a fourth.
That's as unbiased as you will get from me since I make and sell the autocobs now.