Speed plans/pan sizes basics

[ksn3n3]

Hello, speed newbie here.  Been flying CL since the 70s but have not flown speed.  I recently bought some vintage speed pans and am planning on doing some building.  Several of the pans are a Harters and labeled 1/2A,A,B,C on the package.  The pan is about 20 inches long, much larger than the B or D pans I also got, so asuming this is a C pan.  Looking at vintage plans, most seem to be B class.  If I enlarge those plans to fit thr length of this pan, the model looks way too large.  Especially compare to the Top Cat plans which fit the D pan exactly.  I hate to cut down this NOS pan, but not sure if thats the expectation. I did find the Needlenose plans on the site whihc fit this pan exactly and has a very short span, around 20 inches. Still in the plans ordering stage.  Lots of nice plans on the site and probably going to build a Mad John, Lil Dynamite or New Devil.  Any suggestions appreciated.

[FLYACE1946]

You might ask someone who sells plans from the Academy of Model Aeronautics up in Muncie, Indiana .