The painting option makes since opposed to sanding, but what about the times when you're at the field? Should you take a bottle/can of paint with you each and every time you go flying? Maybe making sure your props are balanced before reaching the field would be idea, but not practical.

I sometimes use light bright colors to mark each tip of my prop to act as a safety feature. Since most of my change outs are at the field I find that sanding works best for me.

In order to balance a prop you need a no wind environment if you are at the field then maybe inside the hanger or the inside of your vehicle would be idea. The way I balance which works great for me is the small finger tip balancer sold at your local hobby shop. It is a piece of small all-thread that tapers off to points on each end and has two thread nuts that are designed to fit your prop as they are tightened up on each side of it.

Randy