I have done similar to Post #2. "Standard" RV-6A aft of the firewall, more of a -7A forward of the firewall. Somewhere in the build process of the 6A, I decided to purchase a set of RV-7 preview plans..what a great item that turned out to be. While looking through -7 preview plans to see what the (then new) 7's were like, I found numerious answere to a number of build questions I had on my -6A. I also liked the way the firewall forward areas were different from the -6A design, relocation of the battery box, gascolator, fuel line routings, electrical contactor placements, cabin heater box placement and design, etc.
The biggest help with the -7 plans were in the additional drawing details for the Cowling Instalation (DWG45) and the Tip-up Canopy drawings (DWG 48, 49).