I am using a 2 1/2 foot piece of strap metal from home depot. I just bend it into a "C" shape and bend then ends out so that I can screw it to the 4x4. The one above is NOT mine, but is very similar. I should be able to finish it this weekend.
And now that I have thought about it, rain gutters may not be the solution but downspouts doing NFT just might be