This was extra painful, because I wasn't using one of the OS that is blessed by Hetzner, so it requires a remote install. Remote installs require a system that can run their Java web plugin, and that have a stable and fast enough connection to not time out. The only way I have reliably gotten them to work is by having an ancient Linux VM that was also running in Hetzner, and had the oldest Firefox version I could find that still supported Java in the browser.
My fault for trying to use what they provide in a way that is outside their intended use, and props to them for letting me do it anyway.
