Interesting, never thought of doing the dishwasher before. Just a normal wash setting (without the soap, of course)?
I really don't want to do slate either since I also find it restrictive and I do not want to deal with any drilling. Funny enough, it was the one piece at the LFS without slate (part of the reason I picked it out) and the person at the register suggested that I may need to anchor it because it might float...