Lifetaker or Boltcaster off-hand for Musket?

The plan is to eventually get a Syncretic Musket and run either Boltcaster or Lifetaker as the off hand. Anyone know which would put out more DPS for PvP?

Lifetaker with arcane harness items or Boltcaster with Lightning harness?

Im trying out rough versions of each now and they seem pretty close to each other. BC does give me more mobility and I'm aware of that but which gives out more pure damage?

Additionally, would either of these be viable in PvE? I'm aware ranged dps is kinda frowned upon for putting extra work on the healer but just checking.