I charge per sq. foot. I have a flat price for 7" reveal, small increase for over 8', a small increase for every inch the reveal narrows, and another square footage price for hardie shingle or hardie panel. Heck, if you are really a contractor, why aren't you siding your own house?? As to the price, prices vary with regions and the what your house looks like- is it all "cut up"? Are there dormers, etc.