Welcome, Jeff!
Grass mats are excellent to use, since they’re safe for nibbling on. I think you can’t go wrong with many mats. If you have too many to cover the tile (and leaving a patch for a cool tummy snooze is a good idea) than you will be able to use them outside the bathroom later to cover carpet areas that might otherwise get chewed or peed on. Sammy pulls up carpet corners, so I have cut the mats and put strips across the tempting spots.
Your bunny will show you its preferences. Sammy will not step onto tile in bathroom or kitchen, but prefers her plain plastic floor of her cage, even after her spay surgery. She loves romping on the carpet. Observing your bunny is the best indicator of how to accommodate him to be comfortable but not destructive. I’ve heard of bunnies so at ease on kitchen floors that they nose their way up to the fridge. You never know.
What’s his name? Please post pictures – we love them! 