Ahhh, the old rule from the Vietnam war pops up again...
... it was calculated 3x, as the V-750 (Guideline) missile was flying around Mach3, while the target was doing something around Mach1.
It is still a valid rule, and it comes from the PN constant.
If the plane and the missile travels at the same speed towards each other ahead, they need to pull the same g for a direct hit.
If the missile does double speed, it needs double g's to achieve direct hit.
etc...
Same g's are not enough at the same speed unless evasion is done in-plane. However, you are right (even if you did not say it, I know you meant it) about one thing that affects all things in aviation: The real answer tends to be 'It Depends'
They calculated, that with the proportional guidance method, the V-880 flying, it is capable to hit targets flying at:
Htgt= 1..5km pulling 5..7g (fighters of the 70')
Htgt= 10..11km pulling 3..5g (AWACS, standoff jammers)
Htgt= 20km pulling 1,5..2,5g (HABU)
Must have been pretty slow fighters, without out-of-plane maneuvers. I don't think an AWACS could pull 5g if it's life depended on it.
