I figured out my thread problem on my Finicky Juki!
My Juki has a horizontal spool holder instead of a vertical one. I've found if I use topstitch needles and a (cone) spool stand I don't have the problem with thread breakage, even when doing FMQ. Each thread brand I've tried now works.
And, since the eye of the topstitch needle is larger it's easier to thread and I have less lint - even with CT thread.