This is actually an interesting subject. With today's (old and new) technology one has several choices to accomplish something like this. It depends on the goals, tools available, time and maybe budget.

If the goal is absolute "perfection" then acquiring a recording from a masterful muscian may be the choice.

If improving your MIDI skills and producing a note for note output is the goal, then doing MIDI yourself could work.

If the satisfaction and growth from playing a physical instrument is important, then working with a physical flute or keyboard might make sense.

If staying within BiaB is important, then an RT might be your choice even though, note for note you may not get close to the original. But some covers intentionally do not want to duplicate the original note for note.

Personally, I have BiaB, my bass guitar, a capable keyboard, a drum pad, drum machines, a software sequencer, and human collaborators available (so far I haven't touched MIDI). So when constructing a new song I find the inevitable decision trees all part of the fun.

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BiaB 2025 Windows
For me there’s no better place in the band than to have one leg in the harmony world and the other in the percussive. Thank you Paul Tutmarc and Leo Fender.