Don't make the same mistake I did! 100% agree with everyone's take on assembly sequence so far but I'll add my two cents. I disassembled my doors 8 months ago. I intended to replace all the innards so I did not spend any time studying how they would go back together. My goal was to leave all exterior trim off until post paint. With both doors assembled I did the initial test fit and alignment this weekend and was satisfied with the result. Here's the rub. My '48 has the SS trim at the door glass openings. When I looked closely at the trim I discovered there are retaining tabs that go under the run channel felts!
The doors are coming off anyway, but now I'll probably end up disassembling both doors to install the trim. While I'm at it, I'm going to cut-in the exterior color around the window openings. Hope this little bit of heartburn saves someone some time.