I think my green Churchill Open Road clone took about two weeks -- they cleaned the hat, trimmed the brim and rebound it beautifully. (They also rebashed it into a teardrop, which I had not asked for, but which I ended up liking. Be sure you state clearly what you want.)
Come to think of it, I have a grand Resistol OR clone that could use a cleaning and a restitching of the sweatband, and a green Crofut & Knapp teardrop fedora that could use cleaning and a sizing down. How far down can a hat reasonably be resized? From 7 1/4 to 7 1/8, say?