Hi !
Your shop is beautiful. Just added you in my faves ^^
About banners, I used to change my banner. But I think the best is to keep the one you love. Customers and Etsy sellers can easily recognize you with one banner. If you change too often, it's not so good, as I noticed. So I would stick to the best one ;-).
Having a clear banner, related to your shop, with the colors in your shop is also very important.
I think you have great sales !
Mine are not so good at all, sadly...