Sorry I don't have specific answers for you right off the top of my head.
But here are couple of my fav PPC blogs that blog lots about Adwords and have some posts about QS and the content network.
Adwords | CDF Networks - Affiliate Marketing Blog
Rocking the Adwords Placement Network
Don’t believe the hype - content converts | CDF Networks - Affiliate Marketing Blog
A note on Quality Score! | Cash Tactics
PPC | Cash Tactics
I know I've read some other posts that would answer some of your Qs.
I may be able to find some more when I'm not so tired.