I plan on making one too! I plan on using Zig Millenium or Pigma Micron pens, size 05. I don't like the finer point pens, this size is more of a medium tip.
I have searched google and read a lot recently! What I've read is not to use Sharpies but to use these archival pens. And be sure to heat set the signatures with a hot iron.
good luck!