I have another Hamilton 917 movement that I have been poking at and considering the recent result of my first dial refinish attempt, figure I would continue to discover other methods to reusing an existing dial.
First step is to remove the numbers and to do that, I have sharpened a small screwdriver to a fine point to be able to pry the numbers off gently.
Next I use 0000 steel wool and scrub the dial in a circular motion to minimize cross hatching when taking the print off. Once the dial is stripped of the original, use rouge and a cloth wheel (felt wheel for dremel owners) and buff until gloss but keep in mind that the waterslide decal will need something to grip so I wouldn't recommend going true mirror polish. Keep in mind also with waterslide decals being transparent, if you are using a lighter design, you should take measure to eliminate gouges on the surface previous to the buff stage.
Once I am done polishing to where I need it to be, i hit the surface with my thumb than polish whatever oil that deposited to the polished surface to give it additional grit for the watreslide to adhere to. Dial is now prepped for a waterslide decal, I plan to change the design with this dial to retain the original circular machine marks around the border.