getting a little snarky there, lynard w the HS stuff, no?
look, i'm not sure what that has to do with anything relevant to this thread, but since you bring it up...i'm not gonna apologize for having learned to read and write standard notation while still in HS. if snark and sarcasm helps you deal w it....go for it. (still, i'm not sure WHY that would stick in your craw, but whatev)
as far as playing inversions of 7th chords....nowhere is it written that you must include all four notes! you simply decide which note you want on top/which you want on the bottom of the voicing. the fifth is the first one to go and toss aside as it does nothing to define the "quality" of the chord....as in whether it's major, dominant seventh, or minor. the next to lose is the root (someone else like the bassist is already likely supplying the root)
freddie green is widely acknowledged as one of the greatest rhythm gtrsts ever, and he mainly played two note "shell voicings" that use only the "guide tones" of a chord.....the third and seventh. he also played lots of stuff strumming just one note on one his middle strings while muting the others.
point being, you don't always need six notes... or even four note to play cool chords.
happy chording, all!