Going back a little........ I learned to fly on Auster Autocrats, and did at least 100 hours on them since, so I was ummm - surprised - by this remark;
It doesn't just depend on the engine's D.O.R., it's mostly the prop.
What I learned, and the Auster demonstrated admirably, was that gyroscopic precession ruled, so of course it's the prop, and to a much lesser extent the rotating bits in the engine, but the direction of rotation governs which way the precession will operate.
On a trip in the Navy's Sea Fury, the pilot showed me - very carefully - just how sensitive that aircraft was to injudicious throttle opening at the start of the roll, and careless raising of the tail during it, while still below the airspeed needed to give the rudder some bite.
And whereas in an Auster a ground loop was always a possible punishment for poor handling, in a Sea Fury it was pretty much inevitable if the pilot was careless.