My company does about 60 % comercial work the rest is industrial. I'm currently doing a tenant fitup for a nation wide Gc. The bottom line on my end is follow the print that our estimator bid on.... Anything above or beyond, is a change order, EXTRA $$. Don't be shy, and don't just do what you know, or the inspector says. Do all work per the print. If you see a problem get it in writing!!!! The print which you bid on is your bible. The customer is always right, after they sign for changes..The other thing I can tell you is if you deviate from specs provided to you the customer may nail you, so read the specs several times. If you are sharp you should be able to make some money and have a satisfied Gc, and end customers.