no need for wire mesh or anything. the only thing to be careful of is to make sure that your mortar is mixed properly, not to dry or to wet or it wont stick. also, once you stick the stone on, you cant take it off to reposition it or move it around to much or it wont end up sticking.
you will have to do some cutting – but its pretty easy with a grinder. we ended up buying a cheap one from harbor freight and it worked great.
you can see that we did outline the arch in stones, we did that very 1st before we started stacking.
once the arch 