Hello Stephen,
There are not too many rules: With PERFORMANCES articulations, as they were called in Vienna Instruments collections (= authentically connected notes like legato and repetitions), it's all about playing the connected note within a certain amount of time.
The "timer" resets after a few milliseconds (shorter times for fast articulations like staccato repetitions, longer times for slower articulations. That should help you to get an authentic start note after a certain time (imagine a trumpet player who has to start with a fresh attack instead of a connected note when the trumpet is still "activated").
For Legato Blur, overlaps are the key for a smoother legato when using this fader.
That should be it.
I'll try to fit that in with an upcoming video as well.
Best,
Paul
Paul Kopf Head of Product Marketing, Social Media and Support