Planning to take the plunge and start leveling groups for a 10 man team. I already have a lvl 80 dk and lvl 70 hunter, and some mid-level chars that, withe the bonus levels from RAF, will mean I can get 10 chars to 60 with just lvling 5 RAF toons.

My question is, which would be quicker-boosting or using the multiboxing leveling guide I saw here? My dk is tank specced and with frost presence/blood spec can easily solo all the way through ramps (highest instance I've tried without a healer), so boosting wouldn't be a problem for me. If the answer is that boosting is fastest, I'll probably level 8 RAF chars since I'd have to split them into 2 groups of 4 anyway, with the fifth slot being the dk.