I'm specifically thinking about 5th R 4th ...bass to treble... like D G C.
I suppose Gsus4 is the unambiguous symbol for that tone set.
Gmsus4 could be used to indicate minor mode.
I also suppose not resolving the "suspension" is fine. Something like Dmsus4 Emsus4. (But I really dislike sus being used that way. If it didn't resolve, how was it ever suspended? It's like talking about a door that only closes.)
Anyway, I know about the "So What" chord and quartal voicing of tertian chords. Stuff like...
C6add9asE A D G CorDm11asE A D G C F
...but strictly speaking those aren't unambiguous quartal chords. They contain tones for triads.
Two or three fourths seems to be the un-ambiguous quartal chords...
E A D GorE A D
...where you can't re-arrange letters to get triads and thereby implied/inverted tertian chords.
Are the symbols Emsus4 and Asus4 (or Amsus4) the best option to indicate what I'm calling an un-ambiguous quartal chord?