1. What Glen Said.

2. When I used the wipe-on poly, I used thin coats, the "lintest-free" cloth I could find, and I let each coat dry thouroughly (at least 24 to 36 hours) before lightly sanding (I used micro-mesh pads for this), then cleaning, and then applying another coat of poly.

Let the scales dry in a covered container to prevent dust from settling on them. If you don't have something to suspend the scales on while they dry, then only do one side at a time.

3. Patience is key when working with wood. I tried for a slow build up of thin coats rather than one or two thicker coats. It seemed to turn out well.

4. and have fun!

PS: Your scales are looking much more finished now!