Replacing rear-outlet neoprene gasket

Hi,

My floor-mount, rear-outlet toilet is leaking so I plan to replace the gasket. The local plumbing supply store sold me a neoprene gasket that is 3/4'' thick, with a 3 3/8'' ID and 5 1/2'' OD, flat on one side and tapered on the other. I was told this should work fine and that if it didn't I can always go back for the thicker gasket. Are neoprene gaskets "universal" fit? I am assuming that the flat side goes against the wall and the tapered side on the toilet.

I have seen in some discussion threads that an adhesive is supplied with the Zurn neo-seal but in my case, no adhesive came with the gasket. The guys at the plumbing store said that I don't need an adhesive. Is this correct? Is there some sort of adhesive I should use to make sure that I don't spring a leak?

Thanks

The gasket is fine.
The reason you get a gasket with adhesive on one side is because when you go to install a back outlet toilet the gasket goes on the wall and it will fall when you start to push the toilet on and let go of the gasket.

Thanks. So is there a trick to keeping the gasket in place as I am pushing the toilet back onto the wall?

The adhesive can also be used to stick it to the bowl. There is a lot more surface there to work with.