I have been designing earrings, mostly hollow-formed that
customers find very attractive but when they try them on the weight
makes them droop.
Have you tried using omega clips inconjunction with your posts?
Have you tried using oversized earnuts or earnuts over rubber pads?
Have you tried pre-setting the stone and adding some sticky wax to
keep the stone in place so you can try the piece on before the stone
is permanently set? Then you can make adjustments.
Unfortunately, lots of people have thin or soft earlobes that can't
support heavy earrings. Aside from using omega clips, large earnuts,
pads and minimizing weight, make balance a key design element.
Sometimes, depending how you distribute the weight, you can get away
with a slightly hefty earring because it doesn't tip forward or limit
your post placement.
It's hard to explain, but sometimes, when I have hollow backed
earring, I'll attach a .8 to .85mm thick wire to an inner wall or
surface that allows me to run the wire parallel to the front face of
the earring and then bend it up (not a super harsh 90 degrees with
plier nicks, but a smooth bend) at the proper location. I cut the
wire, but still leave it a bit long. I round off the end so it can
be safely tried on. If after trying the earring on, the post
placement isn't correct, I adjust the bend location and swing the
lower arm of the wire laterally as needed. By not making any cuts
in the wire, I can make adjustments.