Customs Walking along the coupster path of consideration

So I really can't say I understand why my Sport was cut on both sides... But as the coupster discussion goes....either extending the tulip panel (pushing the cockpit in) is an option as well as shortening the quarters (I'm assuming forward of the rear wheel well) But how much?? What is the length of a 30-31 roadster from B-piller bottom pulled back to the bottom corner of the front edge of the wheel well?

 

The coupe doors measure roughly 27 inches and roadster doors 22 and change. The roadster quarter makes up that difference 4.5- 5inches.
I can measure my 29 quarter if you want but don't know if 30-31 is different

 

Thanks wheeldog..appreciate the information...and the offer to measure ...I may better stick to the 30-31 reference...IF it indeed is different...but someone may say their the same... let's see. Thanks again.