questions regarding druid charming in permafrost pits

[bridgetroll]

This question is for druid vets who have charm solo'ed in permafrost pits.

Just hit 54 on my druid and got past that pesky magi giant to get to the bear pits in permafrost. Started to charm kill the bears, wolves and spiders in the pit and I have a couple of initial questions:

1. Do you use your highest level root (engulfing roots) when charming?

2. What is the best way to charm the bear pit (4 bear room and the 2 bear room)?

I've seen people say to stack them, charm a bear, let the other bears maul him down to around 5-10%, and then charm another. Question here is whether charming another bear to finish off the old pet (now at low health) would yield full exp provided that i've done 1 point of dmg to him (via root).

3. Is there one method you found to work best in general when clearing the pits? Whether it be an set order of spells you use or lower level spells, etc.

Any tips would be appreciated.

Thanks