For drainage in the bottom use broken pieces of clay pot, larger stones or non-biodegradable styrofoam peanuts, not aquarium gravel.
Always use the pot that the root system demands!!
If you un-pot it and the root system is large, you go up a size. If you un-pot it and the root system is small, go down a size. If the root system fits nicely into the same size pot then use it. You never repot according to the size of the leafy tops, you pot according to root mass because that is where all the action is!!!
