There are two sizes for the pinion nut. Depends what car you have?
the illustration you show above is from a very good German firm I often use, Bertelsbeck Alfa - why don't you just get it from them? (Pinion Nut = Mutter Antriebsflansche in German, that'll keep you busy) they seem to have both the small one and the large one, depending if your car is a 1600/1750 or 2 litre. 40 bucks for the expensive one, 15 bucks for the other! [EDIT: that includes 19% german purchase Tax, which you will not have to pay, being in the States, or at least you will get back]