You play beautifully, and really did that sonata every bit of justice your instrument allows. But if you are going to play on a viola so small that it produces a violin tone, why not go the full way and play on a violin so you can play the high passages as Franck wrote them?
I think even if it's small the timbre contrast merits a visit. E.g. The nasal strain of the upper register gives the piece a different angle (probably highlighted even more live). Also the single RU-vid video takes away the context of the recital, where again this could make a lot of sense depending on the programming choices.
