Multiple bullets per gun
That's interesting to hear. I definitely considered some extreme cases - for instance, for the hit angle, take the normalized score for that angle (eg, kernel density / max kernel density) as the amount of a virtual bullet hit to count it as. Is that something like what you did? Obviously that's biased towards a gun with a pretty flat graph, but even after normalizing I'm not sure if it would favor one of my guns, which have very different looking graphs.
I have a hunch that this type of system should break down (ie, become so noisy that it's counter-productive) very quickly beyond the first few angles - if it helps at all in the first place. But, not being sure on the theoretical level, I definitely felt that on the experimental level, if I couldn't find benefit in using only 2nd/3rd best angles (which also by far carry the most weight), I would not find it by going beyond that.
In any case, I found no improvement in anything I tried, including the variation I'm trying right now that I thought fixed a flaw in 1.6.13's setup. So I'll probably try 1.6.14 with the old VG and see how that goes. I do still think there's potential here.