We're almost at the last step of bathroom remodeling and I'm paranoid that drilling the TP holder in the tile will crack the tile and I'll have a nervous breakdown!

My contractor would be the one to do this and like I said, I'm paranoid because everything looks just fine and dandy. Any words of wisdom out there about minimizing the likelihood of this (apart from hiring Bill & Mongo who I don't think are in my neighborhood)?

This is porcelain tile, large size (17.5" x 10") if that matters.

Thanks.