new sump for 180gal advice needed

Hi guys, I am thinking to order a new sump from the same company I am ordering tank from and I can decide which one exactly would work for my 180gal reef setup. I never had sump before so I guess after the first one I would be more knowledgeable. In any case, I am planning 3 sections for skimmer, refugium and return. I dont want to have any socks installed, want skimmer to handle all the dirt and probably install small pump in skimmer section so detritus wont be collected.
Unsure if it is better to have refugium in second or third chamber , what the the adv and cons ?
Thinking of probably 80-100 gal sump, what would u recommend the height of it ?