I haven't had a sticking problem, but if I do, I'll know where to get those nylon washers! :P I didn't see any indication of how thick those are. I'd need nearly 1/4".
The big problem, no matter which way I go, is that the inside diameter of whatever I use will have to be big enough to clear the threads on the spindle, which makes that same inside diamter too big for the spindle at the base where there are no threads. Getting it centered so it isn't spinning eliptically is where my problem seems to lie.
A giant nut might be a good way to go, if I can find one that fits. :P