What type of ports should I build near the metal rich ringed planets?
What do you want to do with the system?
If you want specific economy types, and especially if you want specific exports produced by those types, then at the moment you need to be extremely careful what you build and where. The system itself may or may not be suitable for some economies. You will need a lot of forward planning and some types of construction may need to be avoided entirely.
If you don't really care about your stations' imports and exports (and resulting consequences like cargo-based mission generation) then you can just build things because they look good. Ringed planets give you the option to build asteroid stations, which you're not going to get elsewhere, and it seems worth building at least one or two of them if you have the patience for T2 constructions.