You actually do know what to do with your space you probably just can't verbalize it. The design phase usually determines function based on the needs and wants of the client. After function is decided we can plug in the cosmetics. After twenty years of designing and building custom work, I have learned the questions to ask that will determine a concept worth developing. The design phase can start immediately.
Construction is based on scope and scale of each project and prior commitments.
There are many factors that determine delivery dates. My first consideration is for clients that I have already made commitments to. There are however occasions that I am ahead of schedule on projects, clients spaces are not ready or I am just plain not busy. Keep in mind that when I commit to your project that someone else behind you may be pushing for quick completion. It's doubtful that you would appreciate if I made you wait so we could get the rush job behind you done.