[Yes the tiles work great. Also I have a wet saw. I have several hundred pounds of dry live rock that I have collected over the years and plan on trying to cut thin wafers for mounting frags as well.
I have used tiles, aragocrete and flower picks. I also saw online that folks were using sprinkler head filters to mount frags as well. That intriged me because they fit right in the holes of the egg crate and really keep the frags where you want them and keeps them from getting knocked over. But, the problem I have using egg crate is it blocks the water flow and it is hard to clean the built up detritus underneath. I use sand, so it is hard to get enough flow under itto keep it clean.
hth]