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it's very hard to rest from playing for a while as it's everything that you live for
For the working musician, like myself, resting is never an option, but, having said that if I am unfotunate enough to sustain some sort of injury that affects my violin playing, I have to rest and let the injury heal.
You have a 16 3/4" viola??!!!!

You'd need enormous hands and very long arms to continue playing a viola that big and not sustain RSI or tendonitis. I think you've already conceeded it's a bit on the large side for you and you're wise to already be looking at a playing smaller instrument. Most women tend to play violas of around 15 1/2".
A smaller viola doesn't necessarily have to sound small. The arching, the thickness of the plates and the depth of the ribs all contribute to the overall tone.