Suzuki Club UK

Hi Guys

I'm renewing the oil seals and dust covers on a Suzuki GS500 year 2004.
Will 2 litres of 10w oil be enough to do both forks?

Also there is a 7mm allen screw in the bottom of each fork and under it there is a copper washer, on all the videos I've watched it says noting about replacing the copper washers, by not replacing them won't this cause oil leaks when the whole fork assembley is put back together and the bike is in use?

My thanks to anyone who can advise

Not really a bike man but in general copper washers are used when they're designed to crush slightly and create a seal, everywhere I remove fittings that require copper washers I always replace them.