have a cutaway drawing of the K2 , K3, K4 . K3 shows the planing step , transom shape and the pointed tailpiece if thats any use ?
Looking at the detail , K2 appears to be of the shovel nose type and K3 a rather more normal speedboat hull shape except for the cockpit & tailpiece. If that's the the case the GA drawing labelled Bluebird II is in fact K3. And that drawing would be useful. Have some detailed pics of K3 scale prop/rudder , cockpit etc in a 3 page article as well as these
If you want a copy send a PM with your email address.