Darkfortune - You can start this mission earlier than lvl 40 I started this mission as a lvl 31 RDM (highest lvl job at the time I started the mission)
I'm not sure exactly how many crystals you need to trade to get this mission, but I completed 3-1 and 3-2 and traded 1 stack to unlock it. Anyone able to confirm the exact amount and edit the page? - Alamah, Bahamut Server.