Music Writing App for Tablet Running Windows

I transcribe Gregorian chants (e.g., antiphons and responsories) from square to modern notation for my church organist from time to time to facilitate his improvised accompaniment of the pieces for our traditional Latin liturgies, particularly when I can't find existing accompaniments online (yes, I have spent a decent amount of time reviewing the St. Jean de Lalande Library on the C.C. Watershed website). I'm particular enough about my written penmanship to where "bubbling in" notes for long, melismatic pieces for hours on end have convinced me with early symptoms of carpal tunnel syndrome that I need to update myself with a music writing app on a tablet to make this more manageable (and less time-consuming!).

I was recently impressed by the writing feature of StaffPad (YouTube link: Discover StaffPad - Writing Music) and decided to invest in a Microsoft SurfacePro when I saw that the app is compatible with Windows. With my involvement with music being merely a hobby, however, I'm reluctant about the app's $90 price tag, especially without a trial period available. So, to you composers out there: Do you have any suggestions for a similar, alternative app for Windows? I am hoping for the following perks/features:

• Non-negotiable: Draw-to-print writing feature as in the demo linked above, specifically on a tablet running Windows
• Free to low-budget
• Staff symbols for chanted music, including:
  
  • Quarter, half, full, and double bars
  • Tenuto marks
• Transposition feature

I hope this discussion is useful for others who approach organ accompaniment for Gregorian chant similarly. Of course, if StaffPad is ultimately the way to go, by all means, feel free to convince me.

Thank you!