I'd highlight that there's multiple options here that require less steps, like using Sandcats, or passwordless email login, but that you've specifically decided none of those options are acceptable. So you're specifically looking for the most complicated use case you can come up with, and then complaining there's nothing simpler. ;)

I do like your rule, regarding people "trying your product", but I don't know if it really applies to setting up a server, because setting up a server of your own is probably the worst way to try something you aren't sure you want to use.

I'd suggest that anyone looking to "try" Sandstorm should be looking at Sandstorm Oasis, which is managed hosting you can try for free. (Along with being an easy place to see "live demos" of any of the apps on it.) If you try it on Oasis, and decide it fits your needs, you're much more likely to implement the additional steps required to configure it how you want it on your own hosting.

I don't think I'd ever personally put in the effort to set up something self-hosted until I already had "tried it".