General Comments
The basic articulation choices are t and r (the dental Italian r, rather than the French or English r). Mostly, leaps seem to be t t, whereas stepwise motion often shows an alternation. In the French style, the typical pattern is t t r t r for consecutive 8ths, with t r going across the beat where possible, and between a pickup note (or anticipation) and its follower. Faster notes (16ths) do not show the t t r t r pattern, but rather one with the beat (t r t r t). Consecutive r’s do not seem to be a normal part of the style.
The double tonguing shown by Quantz is did’ll, which involves a release of air around the sides of the tongue for the second half of the pattern, perhaps akin to the 16th-century descriptions of “lingua riversa” for the fastest articulations.