We didn't do a tub, but did do a custom neo-angle shower with surround in cultured granite(from a cultured marble vendor). The sequence actually took quite a bit of time: 1) Durock the walls, set the subfloor. 2) CM vendor came in to measure for the showerpan, NOT the surround. 3) 1 week to create the showerpan. They installed it, then measured for the surround. 4) Another week for the surround and inserts, which were then installed. 5) Then, and only then, did the shower glass vendor come out to measure for the glass, which of course took another 2 weeks to install plus a day to dry the silicon caulk. So it was a month after we did the order, until we got to use our new shower! Love it, though - people are sure we've got a Corian shower with matching double integral sink vanity. They have no idea we saved at least 30% using cultured granite.

The cement board is an exellent base with no wire mesh necessary. I would recommend using fortified thinset mortar instead of regular mortar - it provides a stronger bond and grabs quicker, although it is a little messier to work with and clean up. BTW, don't buy the premixed thinset, mix it yourself from a bag (okay to buy the bag with fortifier already in it).

I wouldn't worry about the stones falling off. Once the thinset dries overnight, the bond is surprisingly strong. Thinset is basically mortar with some sort of glue in it. I installed "ledge stone" on a block wall about four years ago using fortified thinset. The stone pieces are thin and deep so that the actual area that the thinset holds is small compared to the size of the stone pieces. Not a one has fallen off and you tried to remove them, I suspect the stone would break before the bond failed. I understand the placement issue. It doesn't work well to put up a wood ledge because unlike bricks, there is no straight course to support. You could drill some small holes right below the pieces (the holes can be pretty shallow)as you go and insert nails or wood dowels temporarily to support the pieces. This will add some time to your installation, but it works.

We DIY a metal stud and hardie board grill island using Tejas Textured Stone. It is much lighter weight than real stone. I like the looks of real stone a lot better, though this is not terrible. We removed a tree planting bed and installed flagstone in it's place for a 54" round coffee table with fire pit/fire glass and rock seating wall capped with flagstone that matches the pool retaining wall and coping. In doing so, we removed a flower bed as well, and were quoted to cover the old flowerbed with pavestone pavers, as is the rest of the patio. Only after excavation did our contractor learn our pavers were no longer made, so we opted to move the grill island (which would have been much heavier with real stone), remove the pavers under it and replace with flagstone. Needless to say, now I think the grill island doesn't look as good. I have pavers, oklahoma flagstone and Tejas all competing. The grill is 18 years old and ready to be replaced. So far, we haven't found a new grill to fit this cut out in the island so we may have to rebuild. I would go back with real stone instead of Tejas Textured Stone. The top is Noce 4x4 travertine with Longhorn inserts. The tile has held up exceptionally well and I power was it and seal it once a year. Bird poop, grill grease, ketchup, bbq sauce comes right off.