advice on ploymask fronted glass mosaic

[patl]

Although I've put up mesh backed glass mosaic tiles before. The highest candidate for tiling the shower is a glass mosaic tile which doesn't have a mesh backing, but rather a 'polymask' plastic sheet on the front of the sheet instead. I'm a bit worried that these are going to be a pig to tile with although I guess logically they shouldn't be too much worse than the mesh backed variety as long as the sheet is flat when it hits the cement. Does anyone have any advice on these (or is the advice, don't do it...)
While on the subject of mosaic tiles, the adesilix data sheet seems to advise adding latex (I think) if using over a tanked surface. Does bal mosaic fix also require a different formulation in this setting too?

Thanks,

Pat.