When I had to do the same thing years ago, I just bent the spikes flat using pliers - they went back into the cutouts they are formed from, leaving a (mostly) flat disk to bear against the tile.
Use a setting tool with them - doing them up with a screwdriver mostly works, but there's always one that wants to rotate, and it's a lot more satisfying squeezing them tight than it is spinning madly ...
Cheers, I guess that using the setting tool does make the spikes somewhat redundant.
@moog I think the bigger versions of those could work but would need to open the holes up even more. They look decent though so may pick some up anyway.
When I had to do the same thing years ago, I just bent the spikes flat using pliers - they went back into the cutouts they are formed from, leaving a (mostly) flat disk to bear against the tile.
Use a setting tool with them - doing them up with a screwdriver mostly works, but there's always one that wants to rotate, and it's a lot more satisfying squeezing them tight than it is spinning madly ...