Thanks for the post. And your understanding isn't demented, just slightly askew.
Mushroom/spool/serrated pins do not react on gravity as much as you may think, since there is constant spring pressure involved. What they do react on is the tension applied to the plug when picking.
As the pick is lifting the pin stack and pressure applied, as soon as the mushroom or spool pin clears the top of the plug, it will begin to tilt to one side or the other and jam across the shearline. The more that tension is applied, the more quickly this will occur.
This is the reason that when picking a lock that has these pins in it that it makes it extremely important to have the right amount of tension.
A horizontl keyway, such as that found in a lever handle lock, could potentially make it even more difficult as the mushroom or spool pin will have more of a tendency to "fall" and this is where your gravity portion is partially correct.
The proper key, as opposed to a pick, will not cause problems since it brings all the pins up to the shear line and can hold them all there while the key is being turned.
I hope that's clear enough.
