Hello.
Indeed, clients change their minds along the way, so you need to describe the system with full details before committing to a project.
I've done this kind of work before, however I did it in personal interviews with my clients. How do you think we can do this remotely?
Another issue is I cannot give you a fixed price as I don't know what will I encounter. We need to work on an hourly basis. I charge USD $30 an hour, but we can arrange a different rate depending on the work load.
So you are telling your designer will be in charge of devising wire-frames or mock-ups to go along with the requirement document?
What's the idea you have about the way we could work this remotely?