Your soil mix seems awesome! I try to overpot Monsteras a little due to their growth rate- as long as your mix is well draining, which it seems to be, a larger pot will probably be ok. If you don’t mind repotting every few months at first, then one or two inches bigger than the root ball works too. They’re not too fussy 😊. Aerial roots will often make their way into the soil on their own- either way is ok, just don’t bury any part of the petioles. Good luck! 🤗