The grease cup seal on the upper ball joint: does it sandwich between the control arm and ball joint, or does it fit on the ball joint AFTER the ball joint has been installed on the control arm?

If I'm understanding your question...the rubber boot/cup goes on after the ball joint has been installed in the control arm. Hope this helps!

Yep, you understood my question exactly. The only reason I questioned whether or not it went before or after, is that once you install the ball joint, the nuts are so close to the ball joint, that the cup seal does not fit very well all the on the ball joint. I'll give it a go, though - thanks.