My opinion on this is rather different from everyone else's so please keep that in mind.

When I RaF'd I had accounts A & B, so what I did was A > C > D, B > E. This gave my "main account" more free toons than the secondary.

As for boosting or not MY OPINION is no. Most people will tell you to boost A > B > C and A > D > E. I personally leveled thru LFD and learned how to multibox before I reached 85. The cata dungeons are very difficult to multibox and if you haven't learned the basic's of what to do then its even more difficult.

That being said while you have RaF you wanna level as many toons as possible because leveling post RaF sucks.

I also didn't go the 5x comps, I am weird and did 5 different classes on all my teams. These are my opinions and they are not shared in the community from what all I have read about RaFing. I think I am a better boxer for leveling my teams together, but that is my opinion and its really only worth 2 cents.