Hi Fabionet. I use Rhino as well. Im interested to hear more about the CNC you use & what you mean by 'PVC expanded' material for the plug. Is that medium density tooling foam blank like urethane or similar? You might also want to consider going straight to female molds, but using high density blocks. Here is a link of a friend of mine from Belgium, he has made molds for F5D pylon & other stuff. I think the brand was Sika? The finish on the parts is about the best Ive seen.

http://www.flybiwo.be/home.php?ID=13

By the way, I visited your website & saw a picture of my deck height tool... in Italian! Im afraid I charge $500 'usage fee' per website. OK - you can just send me a Q40 model & we'll call it even. Just kidding.