Have you considered asking this question of adjustable cam gears on a ford eskort forum. I thinks it's FEOA or something like that??? There ought to be plenty of knowledge over there.
So what's with the ZX2 being the third string bench rider?
They are a plenty fine car, although I see your getting 50+ mpg with your wonder wagon...ZX2 adjustable cam gears are easy to find and relatively afordable...TeamZX2.com...