Sorry to say but I think drain screws dissapeared back in the 80s.
Different oil quantities are because one fork does compression only and the other rebound only, can't remember which did which off the top of my head.
If you are going by quantity and not an oil level measurement then I think you would be better off pulling the fork legs off the bike and drain as much old oil out as you can, then refill with those quantities. If you suck the old oil out you will probably have some left in the bottom and end up with too much oil.
Let us know what difference the 5 weight makes when you do it.
Different oil quantities are because one fork does compression only and the other rebound only, can't remember which did which off the top of my head.
If you are going by quantity and not an oil level measurement then I think you would be better off pulling the fork legs off the bike and drain as much old oil out as you can, then refill with those quantities. If you suck the old oil out you will probably have some left in the bottom and end up with too much oil.
Let us know what difference the 5 weight makes when you do it.