what to do?

[Ruth]

Good points Bev. Also don't forget about additional flow and probably skimming if you decide to do SPS.
I think you are going to have to decide what pleases you the most and go with that.
A limiting factor may be that you are going to have a common sump so if you went with one FO or FOWLR and it was an aggressive tank your fish will require additional feeding which can result in higher or increased nitrate which some corals, particularly SPS, do not like.