Tiling on tiles to build up depth

Hi,

I have seen quite a few posts discussing the merits (or lack of) tiling on tiles.

I have a slightly different question;

In my house the previous owners installed cheap looking stainless steel splash backs. The work surface was set in front of these so that when the spalsh back is removed I will have about 20mm if not more to fill before i get to the edge of the worktop. I was wondering if i should put a layer of cheap tiles down and then put the final layer on top. Assuming that the first layer was held on well this should be ok i guess. How long would i need to leave the first layer to dry before i dared put another layer on top?

The wall is a load bearing one so the weight of the extra layer of tiles should not be a problem.

Does anyone else have any other solutions? I have never tiled before so was going to use the cheap 'base coat' as my practice, another reason for using this method.

Alternativly i guess I could put a thickish board up to space the tiles off the wall. I am still not sure what to do at the edge of the tiles though to get it back to the painted wall level.

........or you could build it out with thistle bonding.

I have looked at the Tistle bonding data sheet, is it just a plaster that can be applied in thickish coats? The sheet i looked at did not really say how it is different to plaster.

I am not a plasterer, would it matter if I applied it and it was not totally smooth, the tile adhesive should sort out and minor imperfections i would have thought.

What about fixing a piece of WBP ply (18mm) to the wall with countersunk screws and appropriate plugs and then tiling onto that? Got to be easier and cheaper than tiling and then tiling again and should at least be nice and flat.