The MuseScore version I’m using is not being friendly at all when using both types of notation. The notes on the piano are oddly large, but I think they are still discernable. Alternate fingerings are listed.
Here is a chart. 二上り CGC
一の糸 0 C
二の糸 0 G
三の糸 0 C
IIRC, It’s this post. Musescore Shamisen Font
That’s the method I use ^