I finally worked up the nerve to do the mod I had originally planned for the G-9300GB--reversing the negative to make the display more legible.
1.) First, opening the case: The gasket is a funny shape. The module sits neatly inside but also comes out easily. Be careful not to touch the compass sensor.
2.) Taking out the module. Notice this watch is smart enough to know when it is open and some functions are disabled. Notice also there are a whopping FIVE tiny springs sticking out of this thing. Be careful not to lose these (they don't seem to fall out easily, but you never know. they can be impossible to find sometimes if they do fall out).
3.) I used an x-acto knife with a brand new blade to carefully pry off the old polarizing filter. It is stuck on with adhesive, so it takes a little muscle, but you have to be very careful not to scratch the underlying LCD. Once it's pried enough, you can peel it off like a sticker, while holding one end with a pair of good quality tweezers. Sorry, no pictures of this nerve-wracking step.
4.) The LCD will have some adhesive left on it from the old filter. This must be completely removed. I used about 20 Q-tips soaked in acetone and rubbed it gently for about 10 minutes to get it completely clean. The adhesive comes off slowly, bit by bit. All clean:
6.) I put what was left of the old film on top of my sheet of polarizing film and traced around it with a Sharpie to get the right size. I cut it out with scissors
7.) I peeled off the protective layer on the sticky part of the film, stuck it to the LCD, then smoothed it out to clear all the bubbles, then peeled off the protective layer on the other side of the film. No pictures of this difficult step.
8.) Lastly, put together. Looks like the Dawn Black Mudman. I call this version the Dawn Black Scorpion.
9.) Some shots taken with my cheap point and shoot camera: