I bought an original unopened Maxi Alpha 3 (kit 1903) from the early 1980's and an Executioner (kit 1951). I compared the nose cones in both kits and they are exactly the same shape and size. The only way I can tell the two apart is that the nose cone from the Maxi Alpha is a little "softer" than the one from the Executioner. I'm going to attribute this to different materials used in their construction, since they are around 35 years apart in age.
Since the Maxi Alpha used the same fins as the Colossus, I now have a pattern for the fins.
At this point, I am planning to use the Executioner as the basis for my Colossus clone. To extend the body, I will need to buy an additional BT-80 body tube and coupler. I'll need to get a BT-50 body tube and coupler to extend the engine mount. Then I'll cut new wood fins that match the shape of the ones on the Maxi Alpha III. I could use the fins from the Maxi Alpha III, but I remember the plastic fins having a tendency to break off on the Colossus I had as a kid. Using the Executioner as a basis will give me the ability to use both D and E engines and have through the wall fins.
Once I get an accurate scale drawing made for the Maxi Alpha III fins, I'll have to see if I can post it up somewhere for others to use.