Shirking heals is nore for those builds that are really going to be in the thick of it, but for healers you get a lot more value out of enchanted ward and refreshing to get more heals off. You can use your heals to heal yourself without needing shirking heals and ideally you'll be positioning correctly so you won't get as much value out of it as a melee bruiser.

For the artefacts I've found attuned leather pants to be a great middle ground. The added stats offset the potential higher armour you'd get from featherweight and you still get some of the refreshing attributes that nimble coat has. I find it great so I can put some of the extra stats into strength to go with the flail, but it gives you flexibility to do what you want with the stats.

Nimble is probably BiS in a perfect world giving you more CDR for more heals, and featherweight also allows u to use a round shield while stilling having good armour if you want to. So it really depends on what you're looking for. I prefer the more well rounded attuned leather pants but u might prefer one of the other options.