OK, I’m confused! In the McLaughlin link, everything(?) you’ve said refers to him using even numbers of notes per string, facilitating his UWPS, i.e. 1WPS. There are some clips of his instructional DVD and he even adds an extra note per string to produce an even number when formally laying out the modes, again facilitating 1WPS. I checked some of the improvisational passages, and again all the fast playing seemed to follow this regime. You’ve said it yourself about his patterning. So how is he a “textbook two way pickslanter”?
BTW, he said in an interview about that performance that it was much faster than the rehearsal tempo and it was set by the drummer. He thought, it’s live, just got to go for it.
Edit, OK I’ve seen the 2str Arps now! LOL I really should pay more attention!