I've always like 30/31 coupes better than the 28/29 coupe because of the shape of the cowl and I find a lot more and cheaper 28/29 coupes. I have lots of 30/31 cowls and am tempted to fit one to a 29 coupe to see how it would look. I'd leave the flat belt line on the 29 door and modify the brief piece of double belt line on the cowl and adapt the difference in hinge location. Once you chop the top, I wonder how many people would notice? Has anyone done this before? You can buy 4 foot long sticks of 30/31 double belt line if you really want to make it look like a 30/31 if you wanted to go that far.