Oncidium Varicosum repotting

[Roma Oli]

Hello,

I'd be happy to get your advice on how to repot this orchid. It has been growing in this pot for 2 years and lately been blooming.

It is currently in a 5 in diameter pot, has 3 old pseudobulbs in the center and 2 "branches" of growth with additional pseudobulbs on sides (3 pseudobulbs each). It has quite a lot of aerial roots at a higher level than the media, not sure if they should be left in the air or I should try to move them into media when repotting.

I assume I should get a 6 in (?) pot and repot the whole plant (not sure if 6 in pot is enough). Also, I am wondering if there's any advantage in separating it into two plants.

For media, I am thinking of medium bark mixed with sphagnum moss... It is currently in an oncidium mix sold by rePotme (Small Orchiata Monterey Pine Bark,
Turface MVP and Small Black Lava Rock). I currently water it twice a week (I give it a several minutes shower) but it doesn't seem to be enough.
During the blooming, it got a lot of wrinkled leaves and pseudobulbs, even though I started watering it more often than usual.

It also has some roots with brown tips, not sure why.

Thank you so much!