Build plate spacer, for Rep2 HBP

I recently upgraded to Bottlework's Heated build plate (http://www.bctechnologicalsolutions.com/hbp/index.html). There was a little more play than I would have liked, and inspired by http://www.thingiverse.com/thing:129663 and wanting something better than a shim on a washer balanced on a nut for spacing, I figured I'd try something similar, but a bit taller, as the HBP sits higher.