Folks,
Unless I have missed something in this discussion, I haven't seen any reference to the type of oil engines are using.
Unlike motor oils, few aircraft oils are multi-grade, and when it comes to radials, much the consistency of treacle when cold.
Hence the widespread use of oil tank heaters to bring the oil up to a "flowable" temperature before pre-oiling and starting -- radials.
Likewise, sump or oil tank heaters (and sometimes pre-oilers) are commonly used in colder climates, such as parts of the USA and Canada, or in really cold conditions, heaters for the whole engine --- any type of piston engine.
I can't say I have looked recently (being largely involved with radials) but last time I took much of an interest, I didn't see any multi-grade oils around, and there were certainly none approved for my old IO-470Ms in Australia.
In USA, there are some excellent multi-grade aero engine oils available, but they have not often been approved by the manufacturer (or in the case of Curtis-Wright engines- no manufacturer exists to "approve" them). Of course, FAA being FAA, and not CASA, this is not a problem, the FAA accepts testing by the oil producers.
Bottom line --- how and why you warm up an engine is very dependent on the type and condition of the oil. No way would I use much more than idle rpm until the numbers are "in the green", and where relevant, the oil cooler thermostat is flowing oil through the cooler.
As for "warming up" causing cylinder glazing --- I simply do not believe that is real, and this is the first time I have heard that claim in my operation of piston engines over 50+ years on three continents -- including LOP since the 1960s.
Tootle pip!!