That's pretty much spot on. Or at least, it SHOULD be that way. (I would argue that some instrument skills are next to worthless in some cases but that's a beef I've had with the system from day 1.) It's based on the original numbers I posted: 60% of your dps comes from singing songs so uh . . . you might want better increases to song dps (via instrument mods) over 1-2% crit strike. For that matter, you should always want the same over 50 HP tankey gear.