I have posted a few more photos showing progress on my X23 build.
In the first photo, the roof has been applied along with most of the grabs. I am a stickler for to-scale grabs, rods, piping, etc., so in this case I did not use any of the grabs or wire supplied by Westerfield. I fashioned all of the grabs from 0.009" music wire (a guitar string). While the stainless wire is a little trickier to bend to shape, it is almost impossible to deform once installed.
I also tackled the brake platform before joining the body and the floor. The Westerfield platform was wrong in all three dimensions (too short, too narrow, too thick), and the ratchet-and-pawl mechanism would have ended up too close to the car-end. I fashioned a new one from styrene sheet, and carefully harvested a ratchet-and-pawl from a Tichy platform. The platform supports were fashioned from strips of 0.005" Mylar. The retainer-valve pipe is soft 0.008" brass wire.
With my kit, the sides bowed out rather than in. I used several mini-clamps to bring them tight to the floor, and then carefully ran a healthy amount of CA the length of the seams.
The doors may end up being my least favorite part of this project. I found the instructions concerning the door guides and rub rails to be opaque, despite several re-readings, and the Westerfield photos were of no help. By squinting at a number of prototype photos, I was finally able to deduce how these details should appear, but I deviated from the instructions somewhat in their assembly. The 3x3" spacers behind the lower door track were particularly mysterious, as Westerfield provides no clue as to how many (or the spacing). The prototype photos show 11 rivets (or bolt-heads) along that lower track, so perhaps that is the correct number. Installing these was fiddly work, so I only applied about half that number, enough to adequately support the track.
In the home stretch now, I am attacking the running boards, a few remaining body details, and the all-important (and somewhat daunting) ladders.
Still hoping that more folks will share their experiences building this intriguing and iconic car.