First too big, now too small........

My road bike has handlebars that bulge towards the middle where they
go through the stem, which makes mounting any accessories on it a
PITA.

I just bought a Minoura Swing Grip (http://tinyurl.com/3dgyd6) which
is cool, but now all my accessories which where too small to fit on
the bars are too big to fit on the swing grip!

All of the accessories have a little bit of rubber around the inside
circumference of their clamp, and I think some of them came with extra
bits that I don't have anymore - is it just a matter of heading down
to clark rubber and picking up some thin rubber and making some more
strips to pad out the clamps?

Clayton