Out of likes, but I suppose it would depend on if @Mikos planned on keeping the cabinet going or not. The two 300’s seem reasonable for it, but it’s not quite as big as the projected tent, correct?
Going to a the larger tent, a 600 mh/hps would fit that nice. A cooled hood would probably be necessary, if not would definitely make life easier. If you decided to light that with leds, I may opt for something like 3 of those cheap two cob fixtures if budget is an issue. Should be under $300, and would put more photons in there than 4 small colored led panels.
Probably lots of scenarios that work. You just find the one that makes the most out of what you have and where you want to end up. I would just as easily recommend saving up the cash and getting into something with some more efficient cobs for the bigger tent