The foam is cut with a utility knife and straight edge (where possible) to shape it. It is slow going and I snapped off a piece of foam accidentally around the small rudder conduit space along the bottom outer edge. It was easily repaired with 5 minute epoxy. I drilled numerous small holes in the foam areas that are going to be cut out to minimize the foam splitting in areas where I don't want it to. This seems to be helping but I still have a lot of cutting to do.
