travertine

I am planning on doing a kitchen backsplash in 4 x 4 travertine tumbled tiles.

Previous comments have been made about the need to seal the tiles.  My question, is there any reason I couldn't dunk them in sealer before I start?  I  think this would be a better way to insure all the little crevices and caves would get adequately treated. 

Second question.  I don't want to get grout in all the surface features, and I have never used a grout "pastry" bag.  Is there any reason I couldn't cover the tile faces with tape of contact paper, then grout with a float then uncover?

Thanks in advance.