wall tile

I have two tiles that are diferent thichnes that are going a wall together. What is the best way to make them flush?

Use a thicker bed of thin set under the thinner tile.

I did try using more thin set for the thinner tile. The thin tile is mosaic small squares on a mesh. I could not keep the tiles even with the thicker thin set. Any other ideas?

I could not keep the tiles even with the thicker thin set.

That is correct and you won't either.

Here's what I do:
Gently and gingerly spread loose thinset on the backs of the mosaic sheets taking care not to press hard enough to cause the thinset to push through to the front of the sheets. This is tricky but it can be done. Let the thinset dry overnight. Then when the thinset is thoroughly dry use a piece of sandpaper on a sanding block to file down the thinset to the needed thickness.

Another thing you can do is to spread the thinset on the wall. Again allow it to dry thoroughly then sand it to the needed thickness. Then apply more thinset to fill whatever remains of the grooves. After that pass dries apply the sheets using more thinset. When I use this technique I sometimes have to make my own trowel at the proper width by grinding teeth into a putty knife.

Both application techniques require a lot of extra time but if you don't get in a hurry you'll be rewarded.

Thanks for your help. I will give that a try