By 1972 some of the VPAF pilots had 6+ years combat experience in various MiGs - and im pretty sure they had to be on alert 24/7 during most of that time.
One pilot mentioned a lot is Tranh Hanh - one of the first fighter pilots to complete training in China - became a flight leader of the 921st in 1964, promoted to command the 921st in 1966 - became deputy commander in chief of the VPAF in 1976!! "Considered to have exceptional aeronautical skill". Although he claimed kills is not actually listed in the leading VPAF aces.
sadly he only mentions 3020 in its June 1968 state used by the 923rd - which already has 7 stars on it - and saying it was used by (claimed) 6 kill ace "Le Hai" at that time.
On the 10th May 72 he only lists 2 pilots being shot down in MiG-17s (Nguyen Hang/ Nguyen Van Tho)- but then again he is sticking to what he was given access to in the late 1990s (which you would hope he was doing!!)