Oliver,
That is some amazing amount of detail work you have done. Are you going to "back date" the UH-1C to a B? I only mention it because I'm fairly certain the C's with the 540 rotor system and cambered tail fin were only used as Gunships. Cobra Company has just what you would need to do this.
How did you pick Shark64 for your screen name? The first Unit I was assigned to in Vietnam was the 174th AHC and the Guns were the Sharks. Check out our Web Page www.174ahc.org
Andy did a great UH-1C called Mustang 6. You can do a search and find his post. He also detailed the engine and transmission area.
Thanks for sharing and keep us updated.