Well from my own meandering experiences, it is best to do as many missions as you can while you young. the tokens will be easyier to get... and the missions will be Alot smaller and faster.. when ur small u can pull out 30 missions in 2 nights if u work at it.. maybe more.. when ur big?? ur lucky to get in 3.. so just a lil hint to all you out there who want to know when is the best time to do missions.. lvl 1 - 30 after that.. in my opionion they just get Bigger.. and harder..<-- ussually end up needing a team.
~Herich~ out.
P.S this is only my opinion...