If the top of the flange ring is above the level of the floor that the toilet sits on, a standard ring should be good.sorry, with the 3” flange. Is a standard wax ring OK for that?
With wax you don't want to de-compress the wax after compressing it. So with a dry fit, you should position shims to prevent rocking. Then lift the toilet, set the wax on the flange, and lower the toilet onto the wax and the shims.