All of my adgroups have 2 ads, except for my campaigns that only target the Display Network. These adgroups have 2 text ads, and 2 banner ads each of various sizes. I'm assuming that domains that show my ads will either show a text ad, or a particular sized banner ad, and that I can have 2 types of each ad in these adgroups and still be able to split test each ad type. Is this correct?
I read a google article once - they recommended 5-14 ads per an adgroup, so you could test one against another. I'm doing 4-6 ads per an adgroup, but I'm running only in the display network. Why did you say "except for my campaigns that only target the Display Network". Do you have any special approach for DN ads? Mind to share?