I did suggest an example of such material, post #9 - including; backing track, hints on how to noodle / improvise etc. Not, maybe, for stadium performance level; but a step on the road.A good difference would be a backing track specific to falling in “the meat of the instrument “ ideal range for each instrument. Being able to specify a key when you buy it.
The sort of stuff I can manage and enjoy; though Ed seems more ambitious.
