i can't put an string like (size=10) or (distance=9) in superflat preset

When i create a preset with custom strings like "... minecraft:plains;village(size=100) ..." and them i click "Done" the string get out of the preset. anyway, if i put:

"... minecraft:plains;village{size=100} ..." all that structure that i wan't to add the string doesn't generate in the world.