Thanks for posting, and thanks for sticking with our stuff.
I’d say that’s correct.
When done correctly, 2nps sextuplet patterns feel pretty similar to doing the same motion on a single string with an accent on every sixth note. Similar feeling of smoothness, ease, and speed. If the motion doesn’t feel easy on a single string, with an accent on every sixth note, at the speed you’re going for, then it’s not going to work across the strings either and maybe some change in your form could help.
Specfically, when I do these kinds of lines with a USX motion, I almost always switch into a more Gypsy- or Teemu-style form that involves a little more supination and wrist flexion, and has fingers grazing the body. Here’s what that looks like:
If I do this motion on a single string, it feels very similar to what it feels like across the strings. I don’t suddenly become slower just because I’m changing strings. If anything, the fretting becomes the bottleneck because the index finger gets reused so often. That’s the speed limit for these kinds of phrases, for me anyway.
So using that as the hint, if you will, how is your smoothness on a single string? If you just do a simple sextuplet pattern (Yngwie six-note pattern, Di Meola repeating threes, etc.) with a nice accent on the first note of each six-note group, can you get it going smoothly at the speed you’re looking for? Maybe give that a shot with fingers extended and see what that looks like. Film it if you can and we’ll take a look.