So it's hard because I'm not actually a dialectologist and most of the discussion usually just says "some dialects generalize the her- forms" and as you quite rightly note it's hard to tell if that's actual generalization of one form, or just a spoken form that doesn't affect the ability to distinguish hin/her forms.
The closest I've found so far is https://www.reddit.com/r/German/comments/7lxd47/comment/drzsmeo/ (but, you know, the Alemannen :) and I should have a look at the Sprachatlas as I suspect that may have some info.


it might be this thanks
Hier ist es:







