I was concerned when my arm came out much different than the sample. I e-mailed Scott at Vans, and had him look at my numbers. He sent me the actual numbers of their RV-12. Their weight is 730, with an arm of 81.69. He suggested that my weight on the nose wheel looked heavy. Playing around on Excel, I found that even a small change on the weight of the nose wheel made a huge difference. I also received 6 W&B's from other builders. The distance from the leading edge of the wing to the nose wheel axle also varied from builder to builder. Mine was 40.125, another was 40.375, one was 40.5, 3 were 41, and the last was 40.75 Vans was 39.82. These too make a difference. A slight variation on the nose wheel distance plus a little on the nose wheel weight makes a 1" difference. I'm guessing that the above 2 W&B's really are not one inch apart. I'm also not sure that it makes much difference. With my numbers I tried to come up with real world loading scenarios and coudln't get outside the envelope.