Joined: Aug 2010
Posts: 12,727
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I recall several years ago seeing photos of a DIY bracket someone made by cutting a piece out of a chainring, it was a curved piece of metal with two bolt holes, but it still had the chain teeth on it. Looked weird but probably worked great.
A long rod like you have in the photo might vibrate when you ride, if so that vibration might not be good for the light.
Also, it looks like the back of the light might get tire spray on it when you ride in wet conditions. A lot of dyno powered lights are poorly sealed on back and on the bottom. I think you want your light far enough to the side and high enough so that tire spray is minimized. Maybe you have done that, I can't really tell from the photo. That said, it looks like you have a very good fender setup to aim the water downwards as much as practical.