Mrked out and cut out the the foam blocks. Cutting the grooves in the foam was easy. However, keeping the depth even was not as easy. both the top and bottom sections fit but I am sure there are going to be some large gaps between the foam and the framework once they are sandwiched together. The epoxy will have to fill those areas.
Marked out and grooving almost complete
home made cutter / soldering iron and exacto blade. worked great. just need higher wattage iron.