Redash creator here.

One correction about Redash: Redash is open source and you can host it yourself too, in case you have an issue trusting a 3rd party with your data.

The proxy approach is something I thought about several times, but I am aiming at providing a collaborative tool, where it's easy to share the results and work with others. Depending on a proxy running on a user machine breaks this.

But having said that, I'm sure there are many whose needs Franchise will fit very well. So kudos on launching a great tool! :)