Sump Help

I have a fish only tank 230g and a reef only tank 150g

Now I am trying to Have a combo tank 460 Gallons 520 after the Sump is in place.

My question is what Order should my Sump be in? I have seen and heard of many different configurations.

refugium Or not?
Best Skimmer recommendation?
Other media suggestions for a combo tank?


Any other advice is appreciated