Guild Marks

Is the only way to get guild marks is the odd leve and the 1 guild quest?

any rank 15+ leves
and 3 guild quests

What I don't understand is why offer me [for example] Thaumaturge GP on a rank 40 leve when mine is only rank 12.....

Any class you get to rank 10+ will open up the possibility of gaining guild marks for that job on leves. It does not take into account what rank that actual class is- hence why you will see guild marks for a low level job on a rank 40 leve.

5/8 today, not bad at all, i can live with this

except for that fact i only got 5 more books left to get toal lol, not gonna need marks soon unless i wanna buy all the useless abilities too