Comment 6 for bug 1114643

I somewhat have the impression that things are being mixed up.
Now, I can be wrong, it can be that everyone is clear about this.
In that case ... Sorry to be interfering. :-)
In the other case ... Hope this will help to come to a solution.

At one side we have music with a non-constant tempo that clearly changes and is intended to change.
At the other side we have music that has an intended constant tempo, but because there's a real drummer, it never can be fully constant.
The latter is typical for the pre-drum-machine-age of the nineties. ;-)
Abba with Dancing Queen is from the earlier age and so can never be of a constant tempo.

If anyone was not aware of that, than I'm glad I could straighten this out.

I guess that for the drum-machine-age-music the master sync will do.
For the earlier age, all will depend on the power of the master sync.
How to finally do it? ... I'm sorry ... I don't have the answer. :-(