Just a quick note regarding running while adding pressure to the winding stem-
You are, as I'm sure you all know, adding power to the train while doing this, and additional power will make a sticky movt run, or nearly so.
99.9% of all the watches I see have been neglected, and haven't been serviced in a long time. Depending on the case type, lubricant used, water damage, etc, they are often gummed up with dried oil and dirt. As already noted, the mainspring will be too weak to do anything if it is broken in any coil, but you will feel it slip when you wind the watch a few times.
Anyway, that's my PSA, don't forget to get your watches properly serviced and overhauled, folks, for many years of trouble free use and enjoyment!
Your Friendly Neighbourhood Watchmaker