Id say focus on getting all slots to iLevel80-90 first. Then focusing on BiS. The hat is probably the first piece i will go for since its arguably one of the hardest piece to get in Coil.

Then replace your "of lights" with Coil and AF2 pieces while running Ultima to boost the accessories slot a bit and maybe EMs.

Its nice to have BiS/theorycrafted items - but your first priority should be to bring everything up to ilevel90 - first imho.