There are so many varibles here, it's almost impossible to diagnose. I know you don't want to hear it, but I'd suggest you take it all back apart and start over again. Check part numbers, pictures, and read read read on this forum. The "washer" you might be talking about, could be the "judder" washer. It can be left out, search here. Good luck!
RiiiTurbo said.......
My friend the stock fibers have one with a larger internal diameter so the spring and washer can sit inside it.
This is the innermost fiber.
However when you replace the stock fibers with say MTC ones, they are all the same so there is no room for the spring and washer anymore they are not required then.
(If you do cram them in then the clutch will be jammed).
There is the same amount of fibers as stock.
So you wouldn't add a disk, more replace that OEM one with the larger internal diameter.