I just started playing and I'm curious on how getting a job works. I'm playing a Pugilist and it says I need to be level 30 and level 15 as a Lancer before I can be a Monk. What's the best way to do this?

1) Get to level 10 Pugilist, switch to Lancer and back at 15.
2) Get to level 30 Pugilist, switch to Lancer and do the Monk quest at 15.
3) Get to max level Pugilist before I switch.
4) Something I haven't thought of.

What's the most efficient method?