I’d use medium silver soldier for the whole job (obviously close
your gold bezel with gold solder).
I know a lot of people would use gold solder to join gold and
silver. I used to do it that way too. A wise man, talented
jeweler, and hilarious joke-teller (ok, it was Jurgen Maerz) once
told me to use silver solder when joining anything to silver, and
I’ve been very happy with the results.
One warning though…Make sure you don’t over-heat the gold, as
it will sink right into the silver leaving you with a gold smudge
rather than a band. You’re working with a very thin piece of gold
and you’ll need to be very careful here. If in doubt, solder the
finding on first with medium, and then use a little double easy
solder to attach the gold. Good luck!