If you have a fixed price per unit your taking some risk that you might be to low x 110 units. If so charge accordinly. By the end things should go much faster and you might make out. Charging labor only would be the safest if your rate is high enough to cover OH and proffit. You still have to figure a what if. What if an appenentace wired in every GFI backwords.
I don't like others suppling material. You do loose your chance of mark up. I might add in something like "We reserve the right the reject material the is below the standards of our company".
You might want to think about charging for misc. supplies on each unit. What happens is they say they will give you everything. All the little things you use like scwews, tape, blades, one of these an one of those add up. Eather you waist you time making them get those little things they forgot or you provide them and get it done. $10-20 A unit of your stuff could add up.
The more payouts the better for you. Because you have a labor only slim deal I would bill out at the end of the week for units roughed or compleated.
Just some Ideas,
Tom
