I love all the guitar tweaks, hope the bone experiments work out.
When I had a Taylor 710 a luthier put in a fossilize Mammoth Tusk saddle.
I don't think it made a difference, but it was a nice conversation piece.
More relevant to this discussion here...
My GX came with a custom MacNichols bone saddle that was dyed black.
Here is how it looked after 17 months (sorry I don't have a sharper image)...
Dyes tend to fade. I play outside a lot, so that probably added to the fading problem.
Pigmented ink would have been a longer-lasting choice (I've used pens with black pigmented ink to make some mods on my Strat. Worked OK, might work on the bone saddles, and if some of it comes off, touch ups would be easy), however, the bone saddle was also worn out, so I replaced it with an Obliggato Black Diamond saddle.
Eventually I put the factory saddle back in
~ and as things turned out ~ I like it best.
It has held up well.