Took Reub's (Alnus) advice and tried using a powered drill for sanding the bone bridge pins that were riding high in the bridge. It took about 5 to 7 minutes per pin, with 150 grit sandpaper. It was possible to simply hold the pin within the bit grips of the drill, and use a fold of sandpaper to sand while the drill rotated the pin.
After, I was re-stringing the guitar, and bringing the guitar up to tune. The G-string bridge pin popped out, and shot across the room. (Didn't see where it went.)
So for the next 30 minutes, I combed the room, looking on the rug, within the nearest bookcase, under the chairs and sofa, in the front lobby, just about anywhere I could think the pin might have gone. Bupkis.
As a last ditch effort, I began searching the top of my dining room table. The lazy susan? Nope. The chocolates dish? Nope. The bookstand? Nope. Under the chocolates dish? YES! There you are you bastid!
Well, frustration soon became relief. The G-string was reinstalled and the guitar brought up to tune.
Here's a couple before/after pics of the reworked sanded pins that now sit flush with the bridge. Before, they looked like this:
Now, this: