Wore the Dabrim on my century ride on Monday. Ended up modifying it a bit to account for my helmet's elongated helmet's "occipital lobe" by adding new loops to mount the tension strap below that, while the elastic at the top of the band goes above. Also finally ended up sewing down the loose ends of the existing loops. It does now go on over my sun cover for the helmet itself, but it takes just the right amount of tugging - a lot, but not so much that the helmet pops right through.

On the plus side, I think I got away with a pre-dawn to post-dusk ride without any sunscreen. It really has a lot of coverage - I looked at buying a cheap hat to modify but they don't have nearly as much brim. (Can't really blame it for the gap between shorts and knee pads that did get too much sun).

At my slow speeds I had absolutely no problems with it flopping around.

Rather than testing headlamp compatibility ended up adding some additional loops to it and tying it to my backpack during the brief predawn and longer evening portions of the ride - fine while riding but a little annoying while accessing stuff in the pack.