I really hate to sound like an idiot, but what kinda xp/hr are u seeing soloing BLM? I recently gave up on BLM b/c the invites/party chances reduced to almost nothing (53blm) and I went on to level mnk 75 and nin 64. I am really excited knowing that I can have a high level BLM and it only depends upon my dedication/skill/time. Please let me know. I may actually be capable of doing the Jay-Z of blm (yeah...its been retired more times than he has).
Before 51 it is more or less your average exp party's exp/hour except you don't have to worry about other party members being idiots. That, offset by the deaths in solo and you getting used to each solo camp basically causes them to be equal.
After 51, however, due to AM and a dramatic increase in good gear, solo exp/hour tends to be far better. I was getting 7000-8000 exp/hour in the Pso'Xja camp at 54 and it only increased as I gained levels and shifted camps, and I had some very un-high-quality-gear.