I have several 206, 306, and 319 machines. Love them except for the fact that the needle plate on them are large
and the bobbins are hard to get at. I only use 206x13 needles. Don't like altering the machines. The other needles
could work at low speeds but hit at high speeds. One hit and you have a dull needle at best.
If I need 16 and 18 needles I just use a different type of machine. Like a 15-91. That is the beauty of having a large
collection.