How to cycle through different AppBrain banner themes? Change frequency?

I have seen a drop in my appbrain impressions and clicks. I think it is because I have the appbrain banner that says ‘More free apps’ showing all the time and it is the same color too. I was wondering how do I have it cycle through a couple of different preselected themes and is there a way to let the banner itself show up every other day maybe? Or perhaps every few hours instead of all the time?

Any help would be much appreciated.