Hi,
I would say start levelling gsm now with your leves. That way you can make silver ingots out the ore and sell them (on moogle silver ingots sell between 100 - 200. Get your miner up a bit too so you have better chance of getting silver ore. You can make good money with gsm, plus gsm and mining go hand in hand. Also theres a limit of 99 leves so start using them before you lose out on them