Plug selection 360 Magnum

I'm more interested in the different length's between the two plugs. They both fit the 360 magnum but the ZFR5F11's are slightly longer. Why did mopar use the shorter plugs then switch to the longer plugs? I think they made the switch to the longer nose plugs in 97. Would it benefit me to run the plug with the longer nose since I live 4000 feet above sea level? I've read when your in higher elevation the engine can handle more timing and that's basically what the longer nosed plug would do correct? Fire the mixture that much sooner since it's a little longer.