Alan,
Griffin and Zoell are good additions to your reading materials. Both fill gaps, but not completely. For Zoell you will need several of his works to come up with his complete analysis. Advantage of Zoell is pics. For the Griffin material,I have all of the monologues, and I actually prefer his original work back in the 1990's to the current offering by Charlton. At least for the Victoria series, there was some mix up in matching many of the pics to words. This introduces a degree of confusion that is not there when you just read the original raw text.
If you are a member of
RCNA or the
ANA you can borrow these original works from their library to check them out before you lay out cash to purchase.
Haxby is currently producing a series of articles for Numismatica Canada on the 1859 series. Joining this organization will give you a quarterly newsletter with his articles on 1859 as well as others writing about tokens.
Hope this helps