Thana doesn't just increase damage, it multiplies your damage depending on the target's defense. And it works on all skills/attacks that don't have a fixed damage ratio.
Back on topic, I'm already working on gunslinger guardian ring, my opinion is that no cast on tracking is OP, the damage seems VERY high at the moment and the spam rate is ridiculous. But then again, GS is probably the class with the lowest HP among the ranged jobs, and if i'm not mistaken, you are forced to NOT use fsoldier while on this build, am I right?
And another thing, G. ring was supposed to be a different build, not an improved full buster, that's why the previous developers (Ares and whoever else) added the cast time until someone found a loophole to made it insta-cast.
So the question is, keep the original G. ring effect or the ND G-ring on both rings? I feel like the no-cast one makes people actually play it.
So keeping those points in mind, I'll see what I can do about it. I'll most likely make the donation G ring the same or a LITTLE bit weaker than the current non-donation G ring (ONLY IF I FEEL LIKE THE DAMAGE IS INSANE WHEN I TEST IT, AKA this is not confirmed don't spread rumors THANKS.), and the ND-G will become a weaker version of the donation one