I do have a pirate dagger but I guess I'll ask you guys for details as to how often it keeps up.
I'm more concerned about DG because they cast many more damaging skills that kaahi won't proc for (the mud 1 mostly), and although they all have fairly high aspds I won't be mobbing more than 1-2 at a time (really depends on what the mix of mobs are, but usually not that lucky), so would vampires gift be able to keep up? Or rather is it even worth it? Maybe I'll have to incorporate some manual dps too in which demon/blessing of stars will be plenty.
If you're looking for specific numbers like "with pirate's dagger + no DPS going Vampire's Gift procs on average every x seconds" then I'm unable to provide you that number but perhaps another SG can.
I don't own Fenrir's (Mammoth camping >

) nor a Meg at present, but I used Fenrir's during the trial when it just had VG; the rest is from my observations of other players in Odin's/DG/knowledge.
VG in general isn't worth it for solo scenarios because it's outclassed power-wise. You're better off going for Power-Up and maximizing heat's damage (fighting chant, Meg, etc) to kill them faster before the more damaging skills then relying on it's damage to heal you up.
It's a fun skill though~
VG would work better for farming in certain spots and/or larger party play where you wouldn't want to be using warmth.
Blessing of the Stars + a speed pot would be efficient DPS-wise. I don't think you'd want to risk Demon's blindness in DG given how quickly mobby it can be if you're shooting to pull smaller mobs.