Thanks for the theory and ideas.
The cap thing doesn’t work for me. I have one, but can’t use it this time of year.
Halo is the only solution that works for me.
In my case, I have good ventilation and my sweat effectively evaporates, keeping me cool. I ride fast, so I have a lot of sweat and at speed it evaporates effectively. But when I stop at a stop light, its like being in a rain shower. Sweat just pores into my eyes. Its worse when my helmet pads get saturated. And, its salty!
A cap does not give me good ventilation, and does not effectively catch the sweat from my forehead. I do like the option of a brim/sun-visor. This sweat band, with its yellow sweat rain gutter looked pretty goofy to me. I picked it up on a whim. But nothing is as unobtrusive or as effective as this. I’ve tried. Maybe I would have a different answer if I was bald, lol. (my bald friends love caps under their helmet).