2nd on what Mike said. Red was traditional, but I use thread to compliment the rod or the same color as the wrappings.
For your grip use cork. Use the cheapest you can find.
Wood was traditional. Glue your rattan down with Tite Bond II. Spot your thread with Zap a gap in different places and give the grip a few good coats of spar varnish, Tru Oil, or what ever you're using as thread epoxy. Sand between coats, tack rag it off and coat again if you use spar. Go to ACE Hardware and get a pint. It'll last a long time.