It may be too late for you but a highly detailed set of plans and separate written specifications on every single aspect of the project that the general contractor has agreed to and signed off on is extremely important to protect you from arguments, misunderstandings, and legal problems. I see so many guys on the forum talk about problems with contractors, almost all of which could have been prevented by good plans and specs. When there is any question by either the contractor or owner, the answer is to refer to the documents. If it's in the paperwork, the contractor is responsible. If it's not in the paperwork, then it's an add-on or change order for the owner. This is especially important if the jobsite is far from home and the owner or owner's rep is not on the job every day. When both sides fully understand their responsibilities and scope of work, projects run smoothly.
Glen