The thing to do, and what I'm going to do is to get a spare bobbin case and modify that. Keep the original untouched.
That way you can go which ever way you want without altering the machine itself.
My wife has quilt using her 319 because of the lack of larger size needles. She has some but they don't last forever and once gone ..... then what. So modifying a spare bobbin case for the 15x1 needles simply makes sense.
As for what the purists do on other forums, well they can go pound sand. We don't need them to tell us what we can or cannot do with OUR machines.
Joe