Hi Filip,
As an 18c specialist myself and harpsichord player, I would not be attempting to mimic Bach's musical handwriting. There's really no need. And for people not familiar with that idiosyncrasy you will confuse them, as it is non standard. My aim in engraving is clarity for the player, and this idea takes it away. Besides, if you really want to do Bach manuscripts then pretty soon you need curvilinear tapered beams (which we don't have). Engraving is a different medium to handwriting. I don't think you have to mirror it.
Nevertheless, give it a couple of days and I am sure the learned colleagues on the list will cook something up for you! :-)
In any case, welcome to the Pond!
Andrew