Changing the rear quarters on my Dart conv. from a 69 to a 70

I'm hoping that we can exchange notes if I can contact him. I have communicated through PM with another member that has done the conversion. He did a vertical cut down the quarter between the wheel arch and the marker to do the splice. I'm pretty much convinced that that would be the most logical way of going and at the same time minimizing the work to join the quarters. The rest of the the rear conversion is pretty much just fitting and plug welding all the spot welds that I cut to tear everything apart. The front group is simply putting on fenders , hood ,valances ,bumpers ,grill and other misc. parts in which I have a 2 door I can reference if I need.
If I recall correctly, my 70 340 Dart Swinger had the same head rest as the 69' GTS, not the 69' Swinger ones, that are more squared off. If your finish project is to be a 340 convertible, then I would say it would be called a GTS, which also was not a 70' option.