Standard size plans question

[Paulieb1979]

Hi I was wondering why planes like the standard 540 has multiple plans. Size A, size B, and all in 1? Ok I am now seeing the size difference but both A & B has the same spec sheet that's what confused me.

 

[FoamyDM]

I wish I could help in understanding it better, but I just print and "poster" print to the size I am using.