I agree with David that Matheson’s 18th-c. German is journalistic or chatty here rather than difficult. He’s trying to be entertaining, a bit like he might have been in a music lesson, jollying the gentleman pupil along. The E. translation offered in Probstücke-Digital also looks like an automatic translation, but does offer occasional cross-references, eg. between Probstück 1 & 2.
As well as allowing users to select modern or original clefs, the digital Probstücke edition gives you options for exporting/printing the music out with an empty staff above it, on which to write your own notes & solutions.