As Tommy tunes mentioned....it's all by the piece lol. It was/is sheet mounted goods(the river rock)and,when mounted on the sheets,after grouting,you can actually see grid lines etc...looks like doo-doo. I took the EXTRA time,and pieced it all in 1 at a time. It sucked,but longterm,it looks good.
In 99% of the homes I do in FL,they run the base,prior to tile. They generally hold it up 7/16th-1/2"
I pretty much do only custom new homes,higher end stuff. That work and cliental always seems to be there in this area. Lots of money here,and lots of people with big money,in my area. To add,some smaller builders in this area have closed their doors,as work in general in this area is down substantially.
Establish yourself with the builder/work scope you want to obtain,ALWAYS do your best,and pride yourself over quality verses quanity,and you'll do fine. Offer to do some work for higher end builders,slash your price to get in the door,show them you work in a timely and professional fashion,and you'll have plenty of work!
I have the skills to float/mud walls,but no-one does that here in FL lol. Likewise with countertops I.E. sinkrail/cap. Do you know how to float walls,and if so,is that a plus where you live?