Your hiring practices and willingness to disclose pay are refreshing. It would be interesting to read a more detailed case study on how this works for you.
For me, the paid work day was 8 hours in a Slack chat asking a lot of questions of 1-2 employees. My task was to get familiar with their existing systems by querying these employees. I was asked to prepare a report about what I found.
The guys seemed busy so for a lot of the day I was on my own, waiting for more information.
It was intense, but by the end of the day I had a pretty good sense of the internals. I think it was a good test overall.
It sounds like it worked like we want, kind of! The work days should be more interactive than what you experienced, I think. The really good ones seem to be super busy for the first 4 hours, with 3-4 existing employees interacting. The latter half is frequently quiet if people are on the right track.
I can guess which position you were going through the process for, and it's something that we've been talking about a lot.
One thing we've noticed is that even when it's not perfect, the process we have helps a lot. You had an imperfect work day, but got a good idea of what the actual work is like. I'd rather you have a perfect workday though.