Re: rosewood vs ebony
I have guitars with ebony fretboards, rosewood fretboards, and maple fretboards. While I like all three materials, ebony is my favorite. To my ears, maple is the brightest. I also think the finish plays a role in how bright a guitar sounds. To me, a maple neck with a gloss finish sounds brighter than a maple with a satin finish. Ebony is in between maple and rosewood as far as brightness. As far as playability, once you break the neck in all three feel good (at least to me). I'm just partial to ebony because I like the feel of it more that the other two. While the rosewood fretboard will influence the sound of your Gretsch Electromatic, the two biggest influences are the Gretsch's hollowbody and filtertron pickups. This is what gives a Gretsch archtop its sound. One thing I did find with my Gretsch is that it needed a heavier set of strings to make it sound really good. With the Bigsby and 25.5" scale, it needed a set of jazz strings to make the body vibrate and give it that acoustic quality that a nice archtop will give you. I put a set of D'Addario EJ21 (0.012 to 0.052) on it and changed out the wound 0.024 G with a plain 0.019 G for bending.
My 2 cents.