Nutrax, how large is the sifter supposed to be?? Might try it one day and use my ravioi cutter which I still haven't worked out how to use, though the pasta/spagetti cutter works great.

Just guessing from pasta making generally, and from standard American sifters, I would say 4 cups for 4 eggs, 1 pound, c. 450 grams.
I own Nonni's sifter. It looks a lot like this and holds 5 cups. However, I looked up a lot of ravioli recipes. Those that call for 4 eggs say "3 cups flour" and 1.5 teaspoons salt.
Just for the sake of being a bit persnickety, how large is an American cup? (yes I know I can google it, but it's more fun this way)
and Nutrax, that sifter of yours doesn't look big enough to hold 5 cups, unless of course they are wee little cups...