Where does this rule of thumb come from? I feel like this might be very data dependent and perhaps we shouldn't suggest anything 🤷

This comes from the two arguments

• linthresh should not be much larger than your min value, as that would push too many points into the linear region. But the linear region should not hold much data: 1. The symlog scale was chosen because of it's log scaling. If most interesting stuff is in the linear range, one could have remained on a linear scale. 2. Due to the different scaling, data relations in the lin. vs. Log regimes are not comparable. For clarity there shouldn't be much going on in the linear regime.
• linthresh should not be much smaller than your min value, as that would mean you have empty decades between linthresh and your data - effectively pushing your data to the borders of the plot and leaving a lot of unused space in the center.

Unfortunately, one has to adapt linthresh depending on the data to get a decent looking plot. When I looked into this first I had no idea what value to choose. While you can create datasets that needs special different tuning, I feel the approximate rule of thumb will generally be a good starting point..