How to place banners for the best results?
 

I have a vBulletin forum, and I would like to advertise 10 companies on a sidebar, on the right hand side (always visible, on all pages of the site).

4 of them are better / should be more profitable, and the other six are a little worse. I would not want to rotate banners, and I would like all of them to be visible at all times.

I was thinking to create a widget with the first 4, and put it on the very top of the sidebar, and then create another one, with the other six, and put it underneath the first one (possibly separate it with some generic vBulletin widget, so it looks better, and does not look like too many ads).

I know it is not a rocket science, but I dont have too much experience with this (especially with things like a/b testing, tracking number of clicks on high traffic sites, tracking mouse movements with some kind of softeare, things like that...), and I would like to get the best possible results.

Please let me know, how something like this should be done...

Thank you.