I'm going to run a international campaign with sitescout and i'm going to place ads on this site
http://www.radaronline.com/
As you can see in the screenshot there are several ad spots available:

Now my question is which spot will give me the best ctr? Above the Fold? Would you create ads for every ad dimension and test out all the spots or just pick 1-2 dimensions?
Would be great if a media buyer could chime in and give me some recommendations.
Thanks in advance
Above the fold usually will yeild the highest CTR, as everyone that visits the site will see it, so they have a greater chance of clicking on it. Test out ads of all sizes, as your conv rate/engagement will be different per size.
300x250 above the fold is usually strongest for me, but ya gotta test all.
Sometimes the below the fold placements are wayyyy cheaper. Gotta test them all to see what backs out.
What are you running? I noticed that SiteScout have a lot of limitations on the type of offers you can run on these sites.
Has anyone tried running mobiles w/ sitescout?
sorry if this is a dumb question but I'd really like to know this...
If I were to buy a below-the-fold placement on a site, would I be charged for the impression even if the user never scrolls down to the point where my ad is actually displayed on their screen?
For instance, say I'm paying $1 cpm for a below-the-fold advert. And say 1000 users visit this site but none of them scroll down the page to where my ad is displayed. Would I still be charged $1 even though my ad wasn't ever actually seen?
Yep, if your ad loads you are charged for it. Hence why below the fold CPMs are a lot cheaper.
Cheers for the quick response, I think i understand now 
Page load = Impression (whether ad is immediately visible or not)