I ride my FX off road as well as on and was tired or tearing off rear indicators and their lenses. They hold up astonishingly well to abuse, even dragging across rocks, but ultimately do get destroyed. I also replaced the taillight, front indicators, and headlight with LED to avoid broken filaments. This is a quick and dirty install so I might go back and redo it more cleanly eventually but it's alright for now.
Here's the bracket, made from some thin steel strip I had around, riveted together and screwed into the lens. I had this amber LED strip on hand too so this was a free upgrade for me. When I redo this I want to be a bit more clever about making the LED strip look more continuous and clean.
Not sure what to do with the holes left behind from the removed indicators. Might take the Dremel to it and cut some of the bodywork away.
From the beginning I've always mounted my plate from the bottom holes which cleans up the tail a ton.
It looks washed out by the taillight in photos but in person they're very bright and distinct, even with the brakes on. Very happy with the result!