I had a few problems with my CAD dimensions. While everything was fitting together okay in the CAD system, I noticed that the trap was disproportionate to the real Hero trap, as well as Stefan's Plans. A few measurements on the cassette were off by about 1/8".

It was no problem to just throw the cassette in the milling machine and remove wood to add a thicker piece of wood back in. Everything ended up being straighter and more accurate than it was. Perfect!

Next up was the top piece of cassette. It was no problem to cut out the general size on the bandsaw, and then mill out the center. Everything ended up perfectly in the end.. despite cracking the thin basswood in a few spots. Glue and reinforcement strips fixed that, and now it is just as good and as strong as it out have been otherwise.

Will get pictures soon.