Unfortunately I found lvl 39 to 44 to be a tough level range. There were not great charming spots that I liked until I got to 44 and started doing Ogre guards. You may be able to start those a level or two earlier but from 39 to 42 I think I primarily grouped.
I was looking at some quadding spots for a Druid and it seems like Butcherblock has about 8 mobs that are on Kaladim Citizen faction so if you only kill them nothing in the zone will assist so you have plenty of room to operate. I checked out the setup myself and I don't see why you couldn't charm there. There are 8 of them total and 2 videos to show you both spots below. Mobs appear to be lvl 35 so not sure how well charm will stick but it's in a zone you can easily port to so it may be worth a shot and if nothing else give it a shot in a level or two.
https://www.project1999.com/forums/s...+scroll&page=4