Couldn't comment as I've never used them, only ever used Magura koolstops (which were good back in the day but pap now), heatsink yellows (which I find great except on a smooth rim in the wet) and TNN LGM's which are also great on a grind.
If you want the washers gift Paypal me £1 to dbarratt6@aol.com and PM your address and I'll post a pair out tomorrow after work!