Hi Bob,
The washer takes the friction so that the two metal parts don't wear against each other. I'd stick with the fibre unit opposed to making up another metal component.
As far as I'm aware the rubber boot is not available as a spare, but if you are using a sealed non self centering bearing you won't really need one. It is preferable to have one to keep water out but if they aren't available then what's really your option ?
Cheers,
BB.
