To alleviate stress try to keep a "planning stage" and budget first and the construction portion after planning is complete. You can always revise but, planning, creating, shopping and construction all melded together will force situations that may compromise an optimal design decision. So, thus the reason for my strong distaste for "design/build" contractors, companies and processes. The design-build process will be the tail wagging the dog to a "designer-planner" type such as myself. I wonder what procedure you are following? If just want to get things done it is fine but, if you care a lot about great design it could be hard on you.