Well, it was 22° out this morning. Not quite the 12° that was predicted.
Pulled out the choke, gave the gas pedal a few pumps, pushed the starter button and
voila! Old Henry jumped to life! No block heater, no battery heater, no battery boost, just like in the garage at 60°! The thinner oil seemed to have done the trick. Looks like I can take back the $45.00 block heater and we're good to go!
When all else fails, read the instructions (in the operators manual that says S.A.E. 10 below 32° F) and, above all else, remember to K.I.S.S.*
*Keep It Simple Stupid