Hi again, Brian.
I'm not quite following. I've just had a look through the New Features for BIAB 2025 and the only things I can see related to Playable Realtracks are (a) the release of Set 4 (containing 99 new playable Realtracks; and, (b) the ability to search Playable Realtracks patches. As far as I'm aware (and I'm sure someone will help me out if I'm wrong) the techniques that actually use Playable Realtracks to modify a generated Realtrack are still the same as they were in 2022.
Just in case you have found this document, yet, the 'New Features' PDF is found under "Help | Program Manuals | Program upgrade manual".
Whereabouts did you find the information about 2025 and Realtracks? I may have missed something.
--Noel