so nobody got the flags pics? here are these three I've designed. I'll try to find older flags.

=Flag of Independant Vietnam, 1945
Red represents success and revolution. The five points of the stars represent the workers, the peasants, the soldiers, the intellectuals and the young.

=Flag of old "South Vietnam Empire", of last emperor Bao Dai, 1954
=Flag of old "South Vietnam Republic", Ngo Dinh Diem, Nguyen Van Thieu, etc etc.

=flag of the Army of the South Vietnam Liberation Front, 1963
=flag of the Provisional Revolutionary Government of South Vietnam
***
color signification
yellow = skin (outside)
red = blood (inside)
that's Vovinam (Viet Vo Dao) coding for the grade belts.
So the SVN flag said: 3 same blood (same color) flowing. Probably North + Central + South.
I have same preference as Byron's.
But we can also try to design a new red flag with yellow Vietnam map outlines. The star is an Occidental design. Probably bourgeois Christian.