I love your expression " manufacturing irregularities" for why things just don't make sense some days with our cars. Every time I spend a day adjusting a door I, at some point, tell myself this f'in door doesn't really fit this car! So after about 3 hours of alligator wrestling I usually hope to pronounce the job complete when it doesn't rub in front and latches without any further cursing and self pity.
The quick release window works relatively OK, the rear pop out latch is from a 70s VW bus, it pops open fine but doesn't pop closed so well, the front part from McMaster-Carr . The hardware that Richard included with window I discovered was not designed for window to be removed. My big dream has been to be able to rest my arm on the window ledge and hang out of the window. Getting close. The new weatherstripping from RD is supposed to eventually compress, 5 years later I'm still waiting, any day now.