I'm installing a new toilet onto a tiled floor. The base rocks slightly from side to side when centered over the closet flange. While I hoped that the tile would be perfectly flat, there is still about 1/16 to 3/32 inch gap on the one side. Obviously, I don't want to crank down on the bolts. Can I shim this out? The tile is 12 x 12 inch on a concrete floor.

Most new toilets come with plastic shims. If you done have any just buy some. Shim the toilet all around and then get a good bead of silicone caulk between the toilet and the tile. You can't allow any rocking at all. Since it sounds like you already mounted the toilet and it rocked, you should get another wax seal.

Luckily, it was not installed yet. I thought I'd dry fit it while in between coats of paint on the walls, so I've got some time. I just checked the box again and there were no shims, but I'll pick some up on my next trip to HD. Thanks for the help.