IMHO the old business of turning the engine by the prop X times is just stuff dating back to the old radial engines, which suffered from a hydraulic lock via oil leaking into the bottom cylinders.
If an engine in that condition was started, it could split the cylinder(s) because oil is virtually incompressible.
Hand turning does nothing for the flat-4 and flat-6 engines.
The weak point on a Lyco is that the camshaft gets lubed only by spray once the engine is running, so you can get a lot of wear at that point. Hand turning will not achieve anything there.
Preheating is obviously never a bad thing but it needs to be a lot colder than this
Multigrade oil is a must for year-round operation, too.
There are other "tricks" to warm an engine, but all more complicated, less effective, and not looked well upon in an airport environment.
I want to know more
The biggest issue with preheaters is the electrical supply needed, and the heater not getting stolen