Gregg mentioned in passing on the videos once as I recall that one might also try starting the harmonic slurs with top note as well as the bottom note as written.
I was already doing that off and on a little but now I utilize this to my advantage every time I practice slurs .
Releasing the bottom note on the downbeat 1st try, releasing the top note on the downbeat the 2nd try, releasing the bottom note on the downbeat the 3rd try and so on and so forth till I can check off the box starting the exercise from either the top note or the bottom note.
I find this to be a balanced approach with significant benefits efficiency wize over and above dogging away at the harmonic slurs always launching on the low note.