1. Chord Sub - Starter

2. In jazz and pop when a G Major or G Major 7 appears you can play:
G Major 7 (E form)
G (E Major Form)
G6 - GMaj6 (E Form) 1
3 4 4 2
3 4
0 0 (note ok to mute
the 5th string) 1st string muted on both chords
In jazz and pop when a G Major or G Major 7 appears you can play:
G GMaj7 | GMaj6 GMaj7 || this is a good substitution.

3. Common Progression
In jazz and pop the major to major 6 to major 7 back to major 6 is a common progression.
At the same time The Lovin’ Spoonful (John Sabaston) did You Didn’t Have To Be So Nice with the same progression in the bridge (but in Bb not F).