It mostly depends on if you either have the Gracia weapon or have another way to inflict light damage (i.e. inflict light enchant cards on your weapon, Lightning Sword: Gorun; a level 85 epic), and what you get from hell mode/ToD pots. Regardless, 6pc Gracia will almost definitely overpower any of his Chronicles with the right set up, since it's one of the best non-Epic sets you can have, and most characters are flexible with it if they have the means to deal light damage.

Weapon Master (especially with the recent buffs) is powerful enough to where even chronicle can be decent to keep for a while. In case you don't want to deal with light damage stacking, you could go for either 9pc Afterimage of the Wind or 6pc Over-shoulder (his more balanced, jack-of-all-trades OV set), depending on your weapon. Those work very well with Lightsaber/Katana builds until you get your hands on better gear. If you're Zanbato, Thousand Sword Warrior is very good for those. I only use Bludgeon and SS as swap weapons for their exclusive effects, so I can't really give any solid advice on gearing around those two weapon types.

I'd personally recommend 6pc Over-shoulder Crasher, because the 6 set effect outshines 6pc Afterimage, and that gives you more slots available for any Epics or other good gear to mix it with. 9pc Afterimage beats Over-shoulder, but at the cost of verrrry limited equipment slots for other stuff.

Wouldn't really get you into raids with chronicles, but if you want to ignore raid, then you'll have a powerful WM outside of it with 6pc Over-shoulder mixed with some Epics/Legendaries.

I wouldn't consider Gracia to be his best set to go for, but it is pretty good enough to play comfortable. You could even try mixing 6pc Gracia with some of his 3 set chronicles to see how that plays out for you. As long as you're having fun, I'd say. Mix, match, experiment; you've got the freedom to do so with him, for he has many options to explore gearing-wise. And he has so much versatility with his weapon swapping for all kinds of fun setups (though funding's a pain in the ass as a result, if you build while managing between multiple strong weapons...).

He's capable of other feats with chronicle, such as swap gear like Enigmatic Swordsman and Flawless Technique, but this post is long enough as is, so I'll hold off on that for now.