3 things wrong with doing a one wiper mod on a Z (all Zs).
1: the upper edge of the windshield is concave.
Because of the shorter height length of the glass, it limits the length of the wiper you can use.
2: limits the amount of area wiped.
3: The degree at which the glass wraps around isn't constant. It increases towards the outer edges, it would cause the outer edge of the wiper to not be contact with the glass. Not really a big deal, but when combined with #2, it really limits your visibility.