[Rosewood adjustable saddle (vs bone)]

I once got a beautiful 1967 Gibson Southern Jumbo on a trade - it had a rosewood adjustable saddle and despite being gorgeous it just sounded dead, so I sold it. For some reason, it never once occurred to me back then to simply search out a ceramic saddle and replace the POS rosewood. Man I wish I had that guitar back.

[Plastic Bridge on 1963 Gibson J-50]

Gibson used plastic bridges from 63-64, it was a terrible idea and they were history by '65.

 

You say yours is "showing signs of age" - if it's not broke, don't fix it, as they say. If and when it gives out, have a respectable luthier replace it with a fixed rosewood bridge, don't replace a sh***y bridge with another sh***y bridge.

 

Here's what the underside of your plastic bridge looks like, with all its hardware. You really don't want to replicate all this mess, do you?

 

[New J-160E string advice]

I use these nickel flatwounds on my '97 J-160E ladder braced/ply top/adjustable saddle. The set I have on now is about three years old and still sounds great. I change strings about as often as this country changes Presidents