Adaptor plate. Cut big hole out with a hole saw, then used it to hold in place to use the cylinder to drill the 4 8mm holes. In this pict I have roughed the transfer ports with a drill to make easier work for the dremel to blend the Happy Time (HT) transfer port shape to the Minarelli transfer port shape. You could also hog out the HT case to match the two but not needed I believe.
