https://github.com/projectgus/make_cabana_route
Compared to SavvyCAN, Cabana is a lot less flexible as it's generally designed to do one thing: play back log files and identify signals to add to a DBC file. However, as a result it does this thing very smoothly.
Here's an example of the UI, looking at a known message:
Popping out graphs of signals in that message to the right-hand pane:
Then it's possible to click and drag on a particular segment of the graph (in this case the pre-charge of the inverter) and "zoom" playback so it loops over that section. Then you can go through the rest of the log and look for values that change at the same time:
It's a bit of a complex workflow to get there, but hopefully it's useful for other folks in the same situation.
(I've written a bit more about the process that led me here, on my blog.)