[BerntR]

Does one have to use Single wrist action while applying a hitting technique?

I don't have the complete answer to that. There's plenty of room for component variation without compensation.

But the diff between swinging and hitting starts early in the bs for me. Single vs standard wrist action is essential for the loading condition of pp#1 & pp#3 in the down swing. More of a "reverse dual horizontal" wrist action in the back swing with plenty of lag between pivot and hands for the swing. And more pivot rotation to create dual horizontal or angle hinge for the hitting back swing. I can probably do as long back swing while hitting as swinging, but then I need more shoulder turn for the hit, to get the right shoulder in position to drive the hands down plane. The swing feels more like a drop of the hands under the plane of the right shoulder to me. It's a feel thing, I know, but there is a geometrical difference right shoulder to hands between hitting and swinging and not only the PP#3 rotation. At least for me.

If you want to hit, you need to rotate pp#1 & #3 back on plane before the release. And for a 3 barrel hit, you probably should aim to keep it on plane at all times.

Just my 2cents. I have a feeling that Yoda would have a more systematic and general take on this, with more room for variation. Perhaps OB.Left too. He has a lot of ideas & knowledge about different styles of hitting. Fascinating stuff.