Which charm spell to use?

[Lysander]

I was wondering what the best charm spell to use was as a necro in Howling Stones. I haven't had any problems using Beguile Undead (max level 46) in basement/north, but I asked other people in zone and some said that Thrall of Bones holds better--maybe because of the -10 resist check? Is that worth 300 mana? Just curious if there were any opinions out there.

When I went to West, I started to get double resists, so I assumed that the mobs were too high level there. Do necros like to use Cajole Undead or Thrall of Bones there?

Do enchanters/druids always use the lowest level spell possible as well, or is there a benefit to higher level spells?

Thanks.