I've solo'd BLM nearly all of 19-61 where I'm at now. Just go to town on the Hobgoblin Animalier pets in Bibiki Bay.
Pull with Tier 3 nuke (I use Aero 3), Sleep 2, then finish it off with your pick of AM (I usually go with Freeze or Flare). Can get Chain 3 easily, and if I hurry, can get chain 4. Love getting those Chain 4s for 420 exp (without empress band btw)
Just go BLM/NIN, throw up utsusemi, eat some MP+ and INT+ food (I use Melon Pie +1) throw up Reraise using RR Hairpin, and get to work.