Can you insert space in bars?

[pdxdjazz]

Perhaps I still don't understand your request.
See the 2nd A section ending as well as the final turnaround measures in this example:
'S Wond-ext-bar Example - George Gershwin, Ira Gershwin (1927)


Four chords in one measure, the first two have the extended qualities that you found overlapped in "standard" sized measures. The use of S(small) wasn't needed, and the adjacent Ab(b9b13) and Db(b9b13) and other two chords in the single bar 2nd ending are still readable and works with the player. (as are the chords in the other turnaround bars.

I hope this is helpful.
)BOB