Square Drop Rings
Square drop rings can be tricky – the rims have a tendency to fall through the hole.
Your best bet is to use the file width of the drop ring – so for a 6″ square I’d use a 6″ square piece of glass. Two layers should be fine.
All slumps – and drop rings especially – work best when you run them at low temps for longer times. That allows the glass to heat and stretch evenly.
As far as the height of the drop goes – you’ll need to peek in the kiln every so often at slumping temps to see where it is.
Helios Kiln Glass Studio