I have seen several tutorials for scratch building counters, and mag housings.
mostly these are made from sheets of styrene.
IMHO I would also not look to making a HASBRO conversion at all if you're looking for the kind of accuracy you see in
the above posts.
Hyperfirm vs Resin? I vote for Resin, hollowed out and modded!
soon there will be a aluminzed resin hollow version out there somewhere, ready for a soundboard, and lights.