I'm on my second group now, left the first at 42 for the moment. I'm boosting with a prot pally, heroic geared only.

With regards to SM, the library is AWFUL. I had to run through there to get the sm key for the pally and the aggro reset was beyond evil. The mobs in the library randomly de-aggrod and ran back to their spots. Useless instance for boosting.

Cathedral is great. I pull the entire tunnel & the whole area around the fountain, kill them. Then I pull the higher fountain level including the mobs at the locked door. My third pull involves running up to the captain inside the cathedral, smacking him and killing the rest of the mobs I kite all the 3 pulls to the doorway out of the tunnel. This allows me to simply walk the followers inside the instance and not move an inch after. Plus by running the in-cathedral pull all the way to the corridor, I don't get the irritating end instance healer boss who is a pointless kill and adds 2 minutes onto the fight. If I cast the mana draining doobery on my weapon I can literally go for a nap although I've started singing limmerics about the Abbots.

As a note for everybody, if your leechers aggro the first mob in an instance (because they are too low a level), DO NOT KITE IT OFF. If you do, your leechers will end up getting killed once you've kited the mob which aggrod out of range of its spot. Took me quite a while to work this out. Always kill the first mob in an instance if it aggros on the leechers before you pull.