Re-cutting the neck angle is almost invariably a better solution to the proper neck angle than shimming, once the proper neck angle has been determined. Shims can and do affect the tone of a banjo. However, if you do not have the proper tools, it is very difficult to recut a heelpiece yourself. Fortunately, for us, Wayne Rogers, the owner of Gold Tone banjos can do this for a reasonable fee. The Gold Tone banjo web page may be found by clicking here.
Some people also alter the tone with the coordinator rods.
I am wary of this, because if you throw the tone ring out of round, you can keep it from vibrating properly. And this is critical for the next part of my system. It is also quite possible to ruin a rim by overstressing the coordinator rods, especially the lower one. However, for those of you who are insatiably curious, here is how it is done. This work takes place at the tailpiece end of the upper coordinator rod.