When building the "boat", the spreading of the top longerons tends to pull the top of the firewall back and thus give the engine thrust line a slightly positive angle. This might further explain the need for many KR's to fly with a more nose down attitude. Using the firewall as a reference when building the rest of the airframe would eliminate that possibility also.
In working on copy machines, etc. for 33 years we called this a "build up of tolerances". All components can be within spec ,but at the extremes, and the final result of several components working together or in series is unacceptable. I can't wait to get the KR back in the air. Even with just four flights to date I'm suffering withdrawal symptoms. I hope to be able to post info later today on the selected motel for the Gathering and, with the help of Bob Lee, have a full blown web site up soon. Larry Flesner