This is what I do for bowls, all on the lathe:
Turn and the outside + tenon. Sand the outside to 400 grit. One coat sanding sealer, sand with 400 grit, a second coat of sanding sealer, sand with 400 grit, then wax and buff on the lathe.
Reverse the bowl, and turn the inside. Repeat the above sand/sealer/sand/sealer/sand/wax/buff routine.
Reverse the bowl again, and use a faceplate tape chuck to turn off the tenon and shape the bottom of the bowl. Then do the sand/sealer/sand/sealer/sand/wax/buff routine on the bottom of the bowl.