When the bobbin is in the Towa, it shouldn't bounce - that's a sign of a warped bobbin. For my A1, I like them around 180 to 200. Start there, then adjust your top tension to work with that.
Superior Threads has now added a top thread tester. They also have a chart for each type of machine and what the settings should be for top and bottom threads. You might want to check there.
HTH!!!