For some reason my stepmania doesn't seem to give the current version properly (tried with the nightly build and the 5.0.9 official release) which makes consensual fallback to the default theme (accusing lower than 5.0.9 version), I had to force the version check script to be skipped so I could use the current consensual version.
You most likely have an outdated executable from not installing 5.0.9 cleanly. If you're running the -SSE2 exe, that's the problem. Non-SSE2 support was removed a couple releases ago, so the -SSE2 exe you see is old and shouldn't be there.
As you probably saw, I didn't bother to try to read the version string, and instead just check whether a function exists on ScreenVersionTest. I didn't get around to actually using get_music_file_length, but pre-5.0.9 has a bug in rendering an ActorMultiVertex that is shaped by a spline, which probably clips the letters in my logo animation.
After doing some changes for my needs, save_score.lua works like a charm so thanks for that. Now I wanted another similar script called right as the song starts (i.e. transitioning to the gameplay screen), I figured out how to get the information I need making this save_current.lua and how to add it somewhere based on how the save_score function is called on the evaluation screen overlay, however I have no idea where to put it to be called at the point I want it to, help with that would be appreciated. Also, I'm assuming all those information I'm querying would be already valid as I enter in the gameplay screen, if that's not the case I would need help with that as well.
Other than that the only significant change I noticed is the 'bounciness' on the menus that felt a bit too heavy to the point of being uncomfortable when scrolling through the song wheel.
Stick it in
ScreenGameplay in.lua. That's the in transition for entering ScreenGameplay, and I don't edit it often so you won't get conflicts when updating. Your code should work fine.
For the bounciness, maybe I should add a config variable for the *4 in this:
https://github.com/kyzentun/consensual/blob/master/Scripts/01%20misc.lua#L586
That's what makes everything bounce.
To create the bezier tweens, I had to make a special screen for editing bezier curves interactively and seeing them in action: