Nexus on pebble tile- install tips?

Toto Nexus
Hello all, my plumber will be installing our new Nexus toilet on our new pebble tile. It was a total rehab, so the flanges is in the right place etc... We're just concerned that the nature of the irregular pebbles might cause either cracking of the porceline durining install, or lots of gaps to be filled with all the pebbles that are set slightly lower. Is there some kind of "cushioning" that can go around the base of the toilet - I'm thinking of some material like weather stripping.

Any tips or advice would be appreciated!
Michelle

A pebble floor toilet install?

I would use something like clear PolySeamSeal to caulk around the bowl.
It goes on white, and dries clear.