Katrina, If you are using a closed back you may want to try heavy
pickeling to deplete the copper from the sterling and then
painting clear laquer or fingernail polish or epoxy or ? over the
silver to give it an air tight sealed surface. If not sealed,
even fine silver will tarnish given time and then you’ll have to
remove the stone and polish the silver. Have you considered a
white gold back?
24 seems pretty heavy, but not out of the question. I like 28
0r 30 ga bezel for most of my stones.
I’m spending a year dead for tax purposes.