I am interested in leveling two classes to 60(+).

I am curious if it would be faster to level the 2 classes I want to 60 while dual-boxing, or to level 5 of the same classes to 60 then use RaF levels to instantly level the 2 classes I want to 60.

I will most likely never use the 5 characters I level to 60; I am only interested in the 2 60s.

I am planning to level a Rogue/Warrior and some form of healer. Any suggestions on dual-boxing synergy between a Shaman/Priest/Paladin/Druid and a Rogue/Warrior would be appreciated, as well.

Thanks.