I’m personally not a fan of CMH or HPS. I ditched my big HPS lights for LED/Quantum boards and have never looked back. For a 4x4 I say save your money and invest in an HLG 550 v2 Rspec Quantum Board for about 400 more and grow some of the best flower you’ve ever seen. Personally I myself won’t skimp on lighting. I just spent 3 grand on a couple commercial Verta 8 lights for my big grow area. Hurt to spend it but it was necessary for the results I want.