I leveled my bathroom floor with self level concrete. The toilet drain is now about an inch lower than the floor. How do I shim this? Extra wax rings, plastic shims, or other suggestions?

Thanks

No shims but you can install one or more flange extenders. Kits are available at most box stores and the net. Toilet Flange Extension - How To Install a Toilet Flange Extension

Yep, Bobs got the answer for you. An inch is just too much to trust to an extra was ring.