you can level a team of every class, either method, in way less than 90 days. The downside to RFD is you have to have the trio..tank..healer..dps. If my goal is to have 5 of the same class.. i just alternate the teams/slots to have one tank,one healer and 3 DPS until i have one of each in the end, that and level granting can get it done.