Makes more sense to only choose for the first transposition, but still doesn't resolve bottleneck.
Most of the problem is resolved, but there is still a snag: if octave is derived from previous info after transposition, it is easy to get a new, undefined measure that is out of range (e.g. because transposition was up).
Current version is very fast when it works, but it can get lost in its search tree if it goes out of range with transposition and then moves back to unspecified measure generation.