You are still going to have to safety wire your oil filler cap, oil filter and dipstick anyway, so, even if these washers are OK with CCS, you will still have to do a lot of drilling.
Safety wire your oil filter by snugging a hoseclamp around it and then wiring the clamp to the bike somewhere so that the filter can't unscrew.
Buy some drill bits, safety pliers, safety wire and, most impotrant of all, a spring-loaded centerpunch to start the hole before drilling.
Oh, yeah a spare oil drain plug wouldn't hurt, just in case...
Somewhere there is a thread on this subject where a bunch of really great guys gave me tons of great advice. Do some searching and all of your questions should get answered.
'Hope this helps.