When refreshing my AMP AdSense units today, I noticed that Google is now pushing responsive sizes for AMP, and their new amp-ad code for AdSense appears to have specific recommendations for above-the-fold and below-the-fold slots.
Both of these recommendations weren't in the amp-adsense code last year when I was last working on ad-code, so it might come as much of a surprise to you as it did to me.
The details are here: [
support.google.com...]
Hope that's useful for people here. Most of my pages are now AMP-enabled (the pages themselves are AMP, rather than making a separate version) and I'm seeing good results from doing so.