Down under here we're not allowed roos in residential areas so even though our town is zoned Rural, if you live in an urban area, you're not allowed roos which is terribly disappointing.
Yeah you're taking a risk if someone complains about your roo so you can keep him as long as there isn't any complains from either your neighbours or your local government. Roosters can really be loud and I think rather annoying if they crow the whole day. Yeah unfortunately Roo collars are really iffy and will really depend on the roo itself. If you're lucky to get a whisperer or one that rarely crows that's the best you can do for now until someone decides to breed one that doesn't crow then everyone will be happy and perhaps ordinances may change then.
Looks like it works with quail!
I'll never understand why cities don't allow roosters, my neighbor's dog is ten times louder than any cockerel I've ever had. My solution is just to bring in my boy in at night, he sleeps in a crate with a blackout parrot cover. I put him out after all the neighbors go to work. He crows once or twice around 5 p.m (right before the neighbors get home from work) and that's it, of he crows any other time I certainly can't hear it from inside. Don't know if it's luck or he just doesn't feel like there's competition or danger about, or whatever it is boys crow about.
I have tried the water pistol method unsuccessfully when I had a pen full of noisy male quail trying to out do each other, but I just bred quiet males and solved that problem through genetics, they literally don't call at all after two years of breeding specifically for calm and quiet temperaments.