Are you talking about wiggly eyes such as these: http://cgi.ebay.com/Wiggly-Wiggle-E...main_0&var=&hash=item82630630cc#ht_2148wt_906 - or?The pupil will move in the plastic casing that is glued to the ball, as long as there is enough space.
Just a small black screw, you can judge it yourself by the size of the eye you end up using.
Sorry, but I am just having a bit trouble understanding what you mean 100%.. heh.
Edra, yep, I've contacted them and asked, but so far no reply yet... Thanks for that info, much appriciated.