Caroline, I haven't found the different needles to be a bother. Buy a good number in available sizes. Even if they are discontinued they'll be available for a long time, and with several machines you won't use needles up very quickly. I purchase what I consider a lifetime-plus supply for each machine that uses nonstandard needles, so when it moves on to someone else they will have at least a small number to get started. You could do the modification, but the available needles are the ones I use most of the time, and can always use another machine if a different size/type needle is necessary.
CD, my 306 has a metal plate that a standard repro handcrank is attached to that cants it at the needed angle. It was made by a fellow in Utah, who sold it with the machine on eBay.
Dianne in Colorado