How to indicate fretting hand thumb (T) in fingering for guitar fretboard diagrams?

Hello,

I'm in the process of creating many chord diagrams for students. It's great that MuseScore now includes the ability to show the fingerings for chord diagrams.

The one stumbling block I've come across is in trying to indicate when the fretting hand uses the thumb to press down the note. This is traditionally done using the letter T. The software seems to limit the input to numbers, and specifically numbers from 1-5. Is there a convention where the number 5 is sometimes used for specifying to use the thumb? Or maybe the 5 is used for a different purpose.

One of the most common chords that uses the fretting hand thumb is the D/F# chord where, shown in the screenshots, where the thumb presses on the 6th string. For instance, this chord is used in the song "Eight Miles High" by The Byrds and "Landslide" by Fleetwood Mac.

Looking forward to any insights, suggestions or workarounds you may have for incorporating the T in the fingerings...

Thanks!