Hi Steve, I cant help you with backerboard charges or wall tile charges. But I know here in Fl. for FLOOR tile guys are getting between $1.35-$2.50 per sq. ft. depending on who supplies setting materials and how involved the job is.
Add 25 cents per foot to your normal price if the set is a diaganal set. Also add 25 cents per foot if the tile is "16" in. or larger.
I ask for $2.00 sq. ft. If the job is diag. and "16" inch tiles I ask for $2.50 sq. ft. I hope this helps atleast some. Good luck Steve.
Also: if there are other duties, floating the floor, furniture ect. charge 20-30 $ per hour.