I have a refugium/skimmer sump setup and am impressed with it. I used to have a canister but ended up canning it as it turned into a nitrate factory.
I also had a massive skimmer too. I was big on mech filtration and dsb
filter. But over time my husbandry skills lacked and never devoted the time to my tank.
Slack on my behalf to the point my tank crashed and looked like a nuclear wasteland. I canned the sump all together with everything in it and cleaned the tank out and setup a smaller sump with a refugium / miracle mud and a smaller skimmer that runs 3 hours a day. As for maintenance it's just changing half the mud every year and harvesting the macro algae, as well the usual pump / equipment maintenance that comes around. Found it a lot better as it was easier to maintain and cheaper.
With this setup over time my tank matured a lot better. Life was coming up everywhere and it's the best it's ever been. I had a bleached coral dying come back to full color and has grown back.
Dunno if any of this helps but just my experience. I have a busy lifestyle and this type of setup made up keeping more achievable.
I used to have metal halides as well. But changed to LEDs and works fine. Big advantage for this was my elec bill dropped heaps and my chiller is only used half the time over summer.
Might be some ideas to think about.
Also if u can get ocean water from ya lfs
, that's not bad either.
As for live rock I went with 1.5 - 2 lbs to 1 gallon of tank volume.
Prob getting of the track a bit but just some helpful tips maybe.