Mine is a new grow system, just bought a house. i have the 50g for sps and high flow high light 8bulb ATI, the xenia in low flow e27 Led lights. the thing is IMO, you need to figure what the goal is. A softie frag tank would have different flow and light than an SPS frag tank. A chaeto refugium would be different than a DSB refugium. It all comes to what you want to do, research best way to do it then give it a go. I have grown it all over my 20 years of reefing minus cold tanks and gorgians, in my latest set up everything is tailored to exactly what i want it to grow.
Are you drilling the 40 breeders? It also comes down to how are you planning on running your plumbing and pumps.