By offpage I meant your traffic sources. The variation between keywords is just so high it kinda trumps the other factors.
++ Adsense uses an AUCTION system. Sure you can maximize click through with a huge wall full of text ads. The problem is RPM is going to be better if you limit the number of ad slots. Hence the ideal placement set up being your text ads in your 1st string placement. Then locked image ads in the rest of them. This way you don't have a bunch of B run text ads competing with the high paying clicks for users attention.
* This is totally untrue in the really really competitive outlier niches where the guys at the top position vs 10th position have very similar bids.
-The other problem with a lot of the guruey themes is they have a gazillion configurable options. Deployment / set up time reduction is important. For the most part a gazzilion options just means 90% of them sit their and dont get used. Just hard code your adsense code, bookmarking buttons, ect right into the theme. If you wanna swap in different codes edit the theme source once, instead of every-time you use it.