I would be reluctant to use paper shims behind a shower wall. If one used one of the new roll on water proofing materials like Hydroban between the tile and the backer board the shims would probably be ok, but a more moisture and humidity resistant material would be cheap insurance.
No Probably not The shims are about inch wide Kind of difficult to make a template out of them. M ight work for the tiles to figure out angles because you can cut them to any length from 4 ft down.
yes, they are compatible.
Definite typo These shins are best for building new to existing and matching finish plane of surface. Material to be shimmed does not matter, wether it is drywall, wood, metal, or any other building material you can think of, these shins are excellent
1/16th of an inch