Here's the good news - Hermann Schirmacher scanned the charts and donated a copy to the Mennonite Library and Archives in North Newton, Kansas. I found them because Grandma Online contained a few references to them, so I did a Google search and found that one location where they were housed was at MLA.
Here's an example of just one of the charts. Isn't that amazing! And that's only one of the charts.
|Source: Ulrich Dueck, "West Prussian Mennonite Genealogy Charts," unpublished genealogy chart collection, chart #78. Accessed online at https://mla.bethelks.edu/archives/ms_482/78.jpg on 4 August 2016.|
Now for the bad news - as far as I can tell, no one has indexed these charts. To use, them you have to sort laboriously through each page and check each name. Any volunteers out there who want to do a tremendous service to Mennonite genealogy and advance your own research at the same time?