Daily hunt bill x 3 + 6 beastribe from heavenwards area, 3 days will yield a level , from 50 to 60 range.
This is really a good pace.
Further that mog beastribe coming to Churning Mist soon, that will probably drop to 2.5 days.

This is excluding your rest exp bonus and 3% food plus FC exp bonus.

Besides, if SE is really doing the double exp bonus, that's probably after 4.0, talking of experience from FF11.