When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I seem to remember Barnabas had some small 5-8mm lying around. Not positive on that. You should also be able to buy some universal 1/4" spacers at most any auto parts store.
I already have some 6 or 7mm's (1/4" or so) but it doesn't leave enough stud for my liking. Ideally something with built in studs would be ideal, but 5mm or less would also do the trick.