Sport coupe to standard coupe has been done many times and is pretty straight forward.Go for pulling the quarters on your coupe if you want,its much easier to work as you cite Steve.I found the upper decklid rail and parcel deck provide a good reference for squaring up the quarters as well as the lower panel. My subrail wasn't perfect,it took a few extra rubber shims when mounting the body to the frame,a lot of squaring is done by shimming the body blocks.The best result is like building a house,start true,end true..get that subrail square and the rest is easy I fabbed a body dolly for mine makes life easier as well..