I own an SPF, I love my car, but I have also seen Dean Lampe's RCR up close, its beautiful and has more room on the inside, tilt front bonnet and a few other things that I liked better than my SPF. Also remember both RCR and CAV are less to rust or corrode, I can see that even washing my car could be a hazard to the future of it. SPF is great for the fact its a roller and its just like the original cars. But who said the old cars where perfect? The CAV looks a tad bigger in my eyes but they are awesome, I seen Johann's car in Road American, it was beautiful. I am not sure if you have the time but I would say either RCR or CAV would be a good choice for a build, but if your like me and really don't want to waste several years of what we have left of a life then buy a car that is completed or a SPF roller. I have not read this entire thread but sure I am repeating someone else but this is my thoughts.
Jack