1) I too am exactly in your target audience and I'm psyched to check this out (I'm the solo tech operator of an ecom business and this will exactly scratch an itch I have)
2) I'll echo what I wrote in another comment: It is VERY HN to get concerned about exposing databases, and folks who are posting about the security concerns are not wrong, per se, but also, you are going down a path that many other SaaS apps have successfully gone down, and it's a feature users want and will pay for. So while you should absolutely make sure this is done properly and advise your users not just to expose their databases willy-nilly, don't get psyched out by folks telling you it's a hard no to have to connect a DB directly. Users want this, will pay for it, and you're wise for doing it.