If you bid by the square foot, you'll lose.
If you bid by the device, you'll lose.
You'll not be fair, or cost effective except to the GC. He in turn will markup by an astronomical amount, negating any impact you might have on "fair" or "cost effective".
How do you think the GC makes HIS money?
You are getting sound advice in the 2 above posts, if you choose not to take it, you'll lose.
Know your cost of doing business, and go from there.
