Be sure your contractor has the required personal liability, property damage and worker's compensation insurance for his/her workers and subcontractors. Check with your insurance company to find out if you are covered for any injury or damage that might occur.
When dry-fitting boards to be glued up later, here’s a trick to help you make sure you will be able to get them back together in the right order. After the boards are in the desired position, draw a triangle large enough to cover all the boards of the section. Later, before clamping, just re-create the triangle as you assemble the boards.