I'm in a different but similar business, and I usually do most of the work myself. This may be confusing or unhelpful but it works well for me. I try to keep things simple.

It's all time, materials, subs and overhead.

I know how much I want to make annually so, divide that number by 2000.

Total up my overhead, everything, and divide that by 2000

Add those two numbers together and that's your hourly rate.

Materials have a sliding mark-up based on cost. Less expensive, more of a mark-up, More expensive, less.

Subs that I know work without a hitch, small mark-up. Less predictable subs, larger increase.

So I estimate the time for the job and multiply that by my rate, then add materials and subs.

I've been doing it so long that I don't hardly need to calculate prices, I just know how much each type of job should be and my income is very consistent. After awhile the main thing is to always try to exceed the customers expectations, I'm not really ever thinking about the money because the quotes are almost automatic.