It depends on the precise shape of the metal leaf, and it’s pretty tricky to manually bend them all to be completely consistent. (In particular, if switches are under heavy use, or are stored for a long time pressed down, they bend a bit out of shape; if you look at the side of the click leaf facing the switch housing (away from the slider), it starts out completely straight, but can get a bit of a bend to it; bending it back straight should restore the click.)
Another thing you can do is replace the click leaves with those from new Matias clicky switches.