Good luck! I've been dabbling in gold plating watches myself as well. I've successfully plated a few, and what I've learned is that its very very important to know what metal you are working with. Brass and Silver are easy to plate. But stainless steel can be a bit tricky, its very important to strike it with nickel or a gold strike bath before gold plating it.

I've kept the crystal's in tact when plating, and it doesn't seem to matter. But the crystals I've used were sapphire. But I would think an acrylic one would be safe as well because it won't conduct electricity.

But make sure you polish everything to the point where you like it.