Looks like I screwed up again.

I roughed in the toilet flange and then set my tile floor, failing to realize that the flange would be too low. The flange is about 3/8" below the finished tile and when setting the toilet, the wax ring barley makes contact.

Normally wouldn't mind resetting the flange, but the ceiling is finished below and would hate to rip into that.

Here's what I'm thinking....use the sioux chief raise a ring.

Is this appropriate for a 3/8" gap? does it just sit right on top the existing flange? Would doubling wax rings be better?