Adjusting door to replacement quarter panel gap

I have a 1973 plymouth Duster that I'm currently restoring from the frame up and have run into a problem with door and quarter panel gap adjustment.  I purchased 2 new quarter panels from AMD and they fit pretty well. Where I'm running into issues is in the door gap area. I have tweaked the quarter panel just about every way I can but when I bolt the door up to check the gap out I have about a 1/2" on the top to about a 1/8 gap on the bottom. ( I do have a 1/8 shim at the top of the door from the factory and still have the uneven gap) This is keeping the door straight with the rocker panel. I haven't welded the quarter panel on yet... but don't see how I can make the gap any better since if  I  adjust and do get the gap closer there at the door I run into fitment issues elsewhere on the quarter. One though I have is to grind the bottom edge of the door to widen the gap... but I'm not sure if that is the best idea to do or not. Any video's on the subject or ideas are appreciated.. thanks...  

I ran into a similar issue when installing the quarter on the left side of the Charger i'm working on. Prior to installing the new quarter there was a large gap at the top of the door and smaller at the bottom. This was because this car was hit behind the drivers door which pulled everything back. After installing the new quarter the top gap was very nice but the bottom was really tight. This car also has wheel tubs installed so there are no factory wheel houses for alignment. To cure the bottom tight gap we had to grab the wheel well lip at the front arch area and pull outward,leaving the the pinchweld along the rocker unclamped. This allowed the quarter to shift back at the bottom of the door corner and gave us a very nice gap. While its pulled out have someone clamp the rocker pinch weld area and recheck your gap. not sure what to say about your top gap hard to determine what needs to be done with looking at the car.
Dave
All Classics Restoration  

Dave I posted some pictures of the car at "http://gallery.me.com/bmcentir" I have done exactly as you described that netted the results you see in the last picture of Duster 3 gallery. If I pull any harder on the quarter panel in the opening lip it hikes up the quarter panel so that it no longer fits at the roof or trunk area. This is my first attempt at replacing so much sheet metal and don't know what issues you would normally come across when doing this. I felt I was at the point of either shorting the quarter panel at the bottom, by cutting it at the door edge and grinding it back a tad, then welding it back together ending up with a wider gap at the bottom. Seems fairly drastic on a new quarter panel. I have owned the car since it was brand new and it has only has minor damage on the drivers side of the car. I did replace both the inner and outer wheel well on that side but is was for rust and a very minor ding at the end of the rocker panel. I do have some room to move the door back to close the gap 1/8 to 1/4 so a little widening would work. I had also considered trying to hammer the tight spot back with a dolly but have little to no experience using dollies and don't know if that would be an option. All I've done is stare at it the last couple of days hoping it would fix its self. Any ideas are appreciated.
Brad