A LOT OF STUFF TO DISCUSS HERE
As already stated, block-heaters are same as electric water-heater elements, so no thermostat; they heat up to however many watts they are and cook at that output so long as power is available.
Here is a touchy one :
Gear Reduction Starters-----Actually, genuine gear-reduction starters spin SLOWER than standard starters, hence the name, thus with the same batteries, a gear-reduction starter will spin the engine EASIER, not faster, but it might spin the engine faster than weak batteries could spin it with a plain old starter.
There are starters that step up the gearing and DO spin the engine faster, BUT they require some serious battery-power, as they draw amps accordingly.
I have been using the same old weather-proof mechanical timer that I got at the local hardware years ago for about ten bucks; it is three-prong.
I have it set to come ON about two hours before the wife leaves for work.
When she starts her truck, she moves the cord over to my truck; since she always leaves a couple hours before I do, this works fine.
I have the timer set to go OFF about noon, long after we are gone, but no current is being used and that way I don't have to mess with the settings on those days when we may not leave so early.
Like someone already stated, on below-freezing days/nights, we should plug in the heater to prevent un-necessary abuse to the engine.
It is detrimental to the engine, everytime it is started when icey cold, quickening the failure of seals and such.
I hear people brag about never using the heater; the same people probably leave their horses out in the cold rain also; during cold weather, if the means is available, your engine will be better off being plugged in for a couple hours.
The best engine-heater I ever had was a 1500-watt (or was it 2500??) canister heater that I plumbed in a line off the radiator drain-port and "Y"ed the out-put line into the return-heater-hose.
Many simply splice these type heaters into a heater-hose, but they do not function properly when plumbed thus.
When plumbed such that the cold fluid enters the heater from down low at the bottom of the radiator, it heats this fluid and convection causes the hot fluid to cycle up and into the engine at the return heater-hose inlet, thus cold fluid is constantly being heated and cycled through the system.
After a couple hours of this, my mechanical temperature gauge would be above 100.