Invaluable post Dan!
When you hit the "sweet spot"
for your 1911, you will find that removing the thumb safety becomes as difficult as breathing.
Why do you need to find this "sweet spot"
? Think of this action (removing/installing the thumb safety) in the same way you unlock your car/house door.
The lock has a keyhole;
This action requires a key;
You need to insert the key into the lock. To do this we automatically index the key to fit into the keyhole.
The next time you have your 1911 stripped down to parts, practice/experiment putting the key into the keyhole sands all the other parts This will simplify why the "sweet spot"
is important to understand....and find.
This visual may help;
In sample A. you can see that the thumb safety keeps the sear locked to the hammer.
In sample B. you can see that the thumb safety has rotated down unlocking the sear.
In sample C. the grip safety (the final safety) is rotated up unlocking the trigger and freeing rearward movement of the trigger hoop.