I looked at the Canopus washers on YouTube. I don't think that they are a replacement for plastic.
They seem to be fragile and they will become chewed up quickly.
keep us posted on their quality and function.
Absolutely NOT fragile. They are more sturdy than I thought they would be too.
I've had them on a particular snare for 6-9 months now,and they seem like they hold tension well, & they haven't smushed real flat either. $15 is less than what I paid for the 40 pack. They're pricey, but they do seem to work a bit better than metal and nylon washers, however, I can't say "WOW!" either. Tightscrews work best for keeping a rod where it's set IMO anyway.
As for metal and nylon washers, I have both on different snares (nylon on everything else). They make about as much difference as when I change a head. Each head is going to sound different from the next, so who's to say?
It sounds like "my drum" so, that's where I'm at with them I guess
BUT, I'm not one to argue if someone else can hear/feel the difference with THEIR stuff.
I agree about RIMS type mounts. Don't need them, but I prefer the smaller L-rod type mount. Yamaha's small hex rod never caused any problems either for me.