Then don't use grout. Just use tiles and stack them next to each other and lined a papertowel in between. The tiles will fit well. The papertowel is for when the pee slips in between tiles. When you clean, either remove the dirty tile and rinse it clean/wipe the tile clean and replace the papertowel underneath. I don't use grout because it becomes a hassle should you need to move your beardie and it adds weight should I need to move the tank.
I have temporarily used those glossy type of tiles. It is preferably to use something more ceramic with a nonslippy surface to help keep the beardie's nails short.