I think already know the answer to this, but thought I'd ask more experienced Adsense users.
Most of my ad formats are set to google_ad_type = "text_image";
If I want to test JUST text ads on all my pages (1,000+ pages), do I need to create a new ad and then re-tag all of my pages? Is there any automated way to edit the ad type and NOT have to re-tag with updated code? I can't imagine there is a way to do this.
I guess a better way to test would be to create a new ad unit and just test it on a select number of pages so I don't have to go through the process of re-tagging all of my pages.
If you change the existing ad unit in the Google interface, it'll automatically change on your site. You don't have to replace any code.
Usually takes about ten minutes to half an hour before you'll see the changes.
However, if the end goal is testing, I'm not sure what exactly you're going for with that.
When I test image vs text, I create one ad unit for text only and one ad unit for image only, place custom channels on them for text and image, and rotate them evenly for some amount of time to see which does better.