Just got hit today with the additional amount that will be due him for labor on the job
He wasn't worried about what to charge! LOL. Do some math and see what he charges for his labor per hour.
The quilters in my guild that make quilts for others the charge is 4 x the retail price of all fabrics and supplies used plus the cost of quilting it. Half to be paid upfront, the balance when finished.
DH and I have had learned to call the company in town that has been in business the longest to do what work we need done for the house. We needed new windows we called a window company, new roof we called a roofing company. I would call a siding company. They will have their own installation crews and everything would be in writing up front. Good Luck!