Is it possible that the toilet is not perfectly level on the bottom? It sounds like you did everything else right.
As long as the toilet is seated properly, and anchored properly, could you just use a white caulk to fill in the gap? It doesn't look very prominent to me. Then again, I could be completely wrong - Just a thought!

Yes, caulk. It comes in all kinds of colors. We've always used it in our bathrooms, all the way around the toilets, just like one would caulk a sink or tub.

The toilet and the tiles both could be off a little, and combined that would create the gap. As suggested, caulk is your friend!

Don't worry about it.....it's common with tile. You're just totally obsessing right now so just finish the tile work and grout! :)

After the grout has dried, set the toilet and anchor it. After doing so, if it is so unlevel that it actually rocks you can slip a small piece of wood shim under the high area, tapping it until the edge of the shim is under the toilet. Then caulk.
I always use clear caulk when caulking on top of a colored tile.

After that you'll never see anything unless you're down on your hand and knees with a flashlight!

I would post this in the Bathrooms Forum where you can get the advice of one of the resident tile gurus there.

I have to make a correction. I usually use clear caulk, but if I'm trying to hide an obvious, ugly gap then I'll use a color to match the fixture. If you use white, then smooth the joint so that you have a clean line along the tile. An old credit card works well!

I have read that you shouldn't caulk all the way around a toilet, because if it leaks you may not know it until there is damage under the toilet. Some people caulk about 3/4 of the way around, leaving an area in the back for any possible leakage to escape.

Ooooh my gosh, is my face beet red!

I had 3 windows open doing searches on GW, possibly finding someone else who had already gone through this situation. Figured I might find an answer without having to post.

When the searches didn't bring up a similar situation, I meant to post this on the Bathroom Forum but with 3 windows open, well, I messed up, BIGTIME!

I kept looking for my/this OP on the bathroom forum and after half an hour figured there was another glitch at GW and I was just ready to post it again.

Good thing I decided to do a search on the Decorating Forum or I wouldn't have known that this is where I posted.

Gads --- I'm such Doooofus!

My apologies for my mis-posting but you know what?
I've gotten some great replies right here!

Heading to Home D now to find the caulk stuff.

Thank you ALL !

Also was told not to caulk around toilet because it won't allow the water to leak on top of the tile if -when the wax seal fails. Our 1pc Kohler has the same problem. The only solution for us was to use the shims made out of plastic (?) that were used to level the whirlpool tub. They are a dark brown. The toilet is white, and the tile is light - you cannot see the shims & you can't see the gap.
Our toilet actually rocked when you shifted your weight - very startling in the middle of the nite.

I used the plastic shims, too.

Get your wax ring in place. Get a higher one...I have no idea what you'd ask for, but we had the same problem when we tiled our floors. Dry fit, and it rocked like mad. DH was going to do the caulk thing, but I went to my friendly plumbing supply store and they got me a tall wax ring. Apparently they come in two heights.

DH set the toilet down, we heard the sucking sound of the wax ring doing it's thing, and viola!! no caulk needed, no rocking potty. Also, the plumbing store guys said NONONONO to caulking around the toilet.