I always stealth climb to high ground and range attack them, never had any problems. You can also blow the canister with fire to make it even easier.
Used this my first run through. Second time out the new group climb/jump was too broken - characters simply got stuck in the terrain, no matter what I tried - even separating them, they were unable to climb or jump there.
Instead I ripped through them with ranged - I have no issue using flaming arrows - the area is already on fire from the crash and they are sufficiently grounded in historic reality that I don't consider them a "cheat" - dip and fire, dip and fire.
