this has two effects:
1. thinner and thicker spacers could be printed to accommodate
preferences without having to reprint panels
2. I'm still testing this a bit, but by not having the spacer and panel
be the same (partially hollow) part, I think the lever clickiness is
a bit more pleasing to the ear
the second point is entirely arbitrary, so the first point is the real
benefit, despite me trying this because of the second
Signed-off-by: Brian S. Stephan <bss@incorporeal.org>
