Oblong closet flange seal

[chico]

I am replacing a toilet that sits on an oblong closet flange. Will a standard wax ring suffice, Is there a special wax ring to use or should I split and combine two wax rings for the seal?

[hj]

I hope it is oval rather than oblong, but the only way to seal to it is by mating parts of two rings together. Since it is the "bad" offset collar, do not let wax get into the recess or you will have problems with stoppages.