Yep, I have an account on at least one Falcon forum, but GRM is pretty much always where I look first for anything (probably should've posted under GRM rather than CM, but hey, it's a '63 Ranchero...)
On my 37th reading of the manual I got, I've just arrived at the conclusion that there isn't supposed to be an adjustment for inward/outward angle of the window frame on the door (i.e. how hard the frame would press against the weatherstripping).
It's not that mine's out of adjustment, it's that it's floppy. A previous owner tried welding the frame to the door sheetmetal, but that's A) ugly and B) apparently ineffective, though the latter may be due to the PO's welding...
I had been working under the hope/impression that the inward/outward adjustment of the window track was supposed to be tied to this, and that my problem was the track's attachment to the outer frame had gone south. But that's apparently just to line the window's direction up with the window's track in the upper frame for smooth window-winding action.
So... Anybody run into this? Is it just a matter of trying to do what the PO did by welding it in place, only do it better? Take the door apart completely, separating the inner and outer skins (eww) and weld it in there? Give up and find a replacement door?
This reaffirms my strong distaste for the practice of shutting the door by the window frame (or window in the case of frameless doors).
Just in case anybody finds this while looking for the same info, I got a good reply over at The Ford Falcon News (I'm not sure whether that'll work without being logged in), noting that there are generally three spot welds holding the window frame to the door, and it's not uncommon for them to break.
To fix it, you need to remove the window so you can push the frame inward, drill any remaining spot welds, clean the mating surfaces, and re-do the spot welds with a MIG (doing rosette/plug welds, I assume).
I'm mightily relieved not to be facing unskinning/reskinning the door. Cost/time-wise, I'd probably have replaced it, but I wouldn't want to recycle a door this old, so I'd have ended up tripping over it for the next decade or so 'til someone wanted a door with a broken frame... 
There should be adjuster screws low on the window tracks that move the bottom,and thus the top in and out. It has been years since i did a Ranchero, but just did a Mustang and they are pretty much the same.
In reply to Tim Suddard:
Thanks, but now I'm confused... The tip I got over at The Ford Falcon News suggested that the frame should be fixed (spot welded) in place, and the period shop manual suggests that the adjuster for in/out angle is for getting the glass to run smoothly in the frame, not adjusting the frame.
Moreover, my rear window track is only a press-fit into the bottom of the window frame, pops out by hand, and shows no sign of having been previously attached more firmly (i.e. no busted welds)
Just to muddy the waters, my Internet poking suggests to me that your version may be correct for '64-'65 (and onward?) cars, but they appear to have one more bolted location than the '60-'63 cars? That would make both things make sense, but I could live without the uncertainty. Predictably, I can't find the source of that impression, or any pictures of the rear edges of the doors in question...
I guess I can find out one thing for sure; if the passenger side (which isn't floppy) also has its rear window channel only lightly pressed in place, then that's not what solidifies the window frame.
Boy did I not expect to babble out another four paragraphs in this thread...
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6/17/13 9:40 a.m.
My Pop had a '63 Ranchero. When teh windows started leaking he removed the interior door panel off, and attached 'shim' stuff to the interior side to push it all outward a bit. If memory serves, it was just basic pieces of flat square metal he got at some metal recycler/junk yard/supply place that had a metric ton of old stuff and metal.
If the interior door is anything like my 240SX, simply look for the places where the regulator bolts to the door frame and shim it out a bit. Bottom bolts will draw the top in, top bolts will force it out in angle. I have shimmed the drivers side on my car by using 1/8" of washers at the bolt locations on the bottom. The Falcons should be the same, Mustangs too
