I'm about to do an advance job quest.

[goyagokou]

I am currently a level 31 Rdm what is the best advance job i can sub.

Thank you.

[Discordian]

Jei has a nice discussion on that here
http://www.ffxionline.com/forums/showthread.php?s=&threadid=26968&perpage=&pagenumber=3

Really the best jobs you can use as a sub are the basic jobs.

rdm/blm = more magic power for attack magic, nice MP

rdm/whm = curaga, status curing magic.

rdm/smn = Lots of MP, gets autorefresh when rdm hits 50 / smn25, you can also use carbunkle as a puller.

rdm/nin = a neat fun class however expensive if you start using powder. I hear that this burns out though since in the higher levels you need to be a true casting mage because hits doing do much damage with a rdm.

rdm/drk = A class that gets Drain AND Aspir a whole 10 levels earlier than rdm/blm. That is very usful in my opinion. If you can get aspir at level 40rdm/20drk. Thats a good thing that will server you well. I get jellous when the blms cast it.