In my experience, each vessel will behave differently, depending upon the wind, current and the amount of sail you have up.
You have to experiment with this under all those varying conditions to strike the right balance
It's about balance: headsail, rudder, wind, current etc.
I will heave-to in order to reef the main. To do that, I need to take the pressure off the main. I also need to have the genoa furled properly for the conditions. If I have too much headsail out, she will not settle in.
If you have the right balance of headsail and rudder, you can luff the main..
( not flog).
There are times when you may need a little drive from the main.
I don't think you can apply a hard and fast rule.