Welcome to the forum!
I have not used that LPE yet, so I'm not sure what all it can do. Instead, I would just make one eye, and Group all the parts together (Object menu > Group, or there's a button on the command bar
, or there's a key shortcut).
From there, it depends on your personal preference. To me, this is the easiest way:
-- clone the group (when you click clone, which is this button
(or use the key shortcut) the clone will be right on top of the original)
-- flip horizontal (this button on the Selection tool control bar
)
-- hold the Ctrl key while you drag the clone horizontally and move it into place (if the placement is very particular, you can use Guides and Snapping, to place the cloned eye.
Snapping:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Snapping.htmlGuides:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Snapping.html#Snapping-GuideIf you want to see sort of a mirror "action", do it this way. (Both ways end up with the same results.)
-- click twice on the eye group (not too fast), to reveal the rotation center
-- grab the rotation center, which is a small plus sign or crosshair, in the middle, and drag it to the point which will be halfway between the 2 eyes, which might be the centerline of the face - be sure to hold the Ctrl key while you drag, to make sure it moves perfectly horizontally - or use guides and snapping for precision (the rotation center will snap)
-- clone the group
-- flip it horizontally, it should go right into the place where you want it
Edit
Just playing around with the Mirror Symmetry LPE. I'm still not sure exactly the best way to use it. There's a good chance it's just over my head.