I did a int/dex build as well and loved it. I used the Demi Human Queens Staff and Moonveil Katana upgraded to the max, I may have switched the staff at some point but that took me very far. You should also look into the FP physik tears, especially the Cerulean Hidden Tear + Magic Shrouding Cracked Tear which makes it so easy to blast off some big spells for free and high damage. I especially recommend using it with the Comet Azur to wreck bosses right off the bat.