Thanks for posting this shot enlarged enough to be readable. You mentioned using Sgt. Bilko's shot calculator as a starting point I think. One of the best things about it was it's simplicity of use.
Also I would think that one of the biggest mistakes that is made by many people is estimating wind angle on some of the visually closer wind settings. With variable winds moving the indicator, a 60 degree headwind can move very close to a 45 degree headwind in appearance, for example.
It will be interesting to see what it looks like when you have it completed.
phred952