I came across this RCM review.

Also, I recently picked up a Como Schneurle .61 and an ST S.75. Both are roundheads of the same series as the ST S.61. The Como is basically identical to the ST and uses the same internal parts, AFAIK. Since BPA doesn't limit to 10cc, the .75 would also be a decent choice for a plane like the Calypso.

David