I'm just wondering what are the recommended stats to aim for?

Currently I have just melded Crit and Det as much as possible with basically no regard to Spell speed. My BLM is only iLvL 574 and sitting around:

Crit 1517
Det 1813
DH 1125
Spell Speed 778

Feels a bit slow, but does well in Ex trials. Should I be aiming for a specific Spell speed for optimisation?

Thank you for advice. I tank primarily, but when I do DPS it's BLM so looking to improve where possible.