Yeah, I'm also wondering which shape maj7th you're thinking of that requires that pinky leap. I know the maj7th with 5th string and 6th string roots, so what shape are you playing? I'd like to add that to my vocab

To add to other good advice here, a good pinky "learning" activity I've found is to take any chord, open or barred, and find the "add-on" notes (7ths, minor 7ths, suspendeds, etc) that add tonal color to it. Find those notes and practice getting your 4th and 3rd fingers there ...this can offer a nice vibe and change-of-pace to those "regular" chords shapes and songs we've gotten all too familiar with. Kind of like shaking out the cobwebs and pushing for another flavor. The
physical plus is your pinky (and third) finger learn to move with greater independence from the other "chording" fingers, just as M19 had suggested with the exercise.
(Hey Marty, good to see ya here, man!!

...ok, that was just a shout out

)
Edward