RE: Outboard Hydroplane - Kneel Down Style
Stover won ten consectutive years with that hull, and you're right it's pretty neat how its built. Our family was involved with racing also at that time and Stover lived close so I grew up knowing him around the house as my brothers friend.
That bottom is one of the first hulls I believe that were rounded on the inside edge allowing it to roll up better in the corner.
About the decal I would just try and copy it, re-size it in Microsoft Paint and print it out on sticky-backed label paper if you have lables, cut to size and mist coat it to seal it up.