where am I going wrong?

Have you tried it with the pedal on the floor? It would be best to disconnect the downrod from the pedal. The spring will be a bit more taught, but there is plenty of room to install the washers;LOTS and lots of washers. Actually I used screwdrivers and such, to span both sides at once. but the handles were heavy and some of them wanted to fall back out. No matter, I won!
BTW, does your clutch pedal have the stiffener bracket on it? I think that piece will no longer be needed and it sure gets in the way. I don't recall what I did with mine.I also removed the seat.