I use the rule that if the oil temp is showing nothing 5 squirts, if it is showing a low temp 1 or 2, and if it has just run I do not prime. I’m not sure about 7 though…if 5 doesn’t work I just stop turning the engine over, pump the throttle once or twice (gives a bit of fuel from the accelerator pump) and usually it fires. I have yet to flood the engine. Good luck starting a cold Pa-28 without priming!