I know that it's not easy recipe but you should try. I can help you if you want.

Ingredients for Cake:
2 1/2 cups flour
1 cup warm water
pinch of salt-to taste

Ingredients for filling:
0.5 kg sauerkraut, 17.63 oz
0.2 kg of dried mushrooms, 7.05 oz
1 onion,
salt, pepper

Execution: Pour water over dried mushrooms and let stand for about 1 hour.

After an hour, cook mushrooms until soft in water in which they were soaked.

Sauerkraut pour water and cook for about 15 minutes.

When cooked, drain off and cut the cabbage.

After cooked, drain off mushrooms and cut into very fine or run through a meat grinder.

Dice the onion and fry in oil.

Add the chopped cabbage and sliced mushrooms to the onions.

Season with salt and pepper. Cook for 10 minutes.
Mix flour with salt and add hot water.

Knead the dough.

Roll out the dough.

Trim the appropriate glass shapes.

Then we put the stuffing in the center of the cake.

We combine the two sides, and glue.

Boil water, add a teaspoon of salt and a tablespoon of oil. At the boiling water throw dumplings.

Cook over low heat about 5 minutes. Serve with fried onions.

How many centimeters for glass diameter size?

this is similar to a pierogi/ravioli - you want to use a comfortable size for filling and not too big so that they don't break in boiling water - there's a pic of the plastic cup I've used for years - if that helps -

TheFamiliaKitchen a/k/a The Family Kitchen: Homemade Ravioli

About 10 cm. It can be a little longer