I'm going to keep fiddling with it today. There's got to be a way to make it do what I want! (I dunno why I think that-my computer never does...) I have a hard time believing it can't deal with something as ordinary as cotton thread, given its age.
I also have a date with my OSMG this weekend about a different machine; I'll ask him if he's got any insight/advice while I'm there.