Square settings

Hi there

Can anybody help with this. I have been trying to find a punchplate
for making square settings that has a very steep angle to the side.
The one I have is the standard one you can buy everywhere - I think
the angle is 17 degrees, but this is no good for making a 3 stone
ring - I need something in the order of maybe 10-11 degrees. Any
advice greatly appreciated.

Darryl Green
Auckland NZ