I am a U.S. Army officer currently stationed in Heidelberg, Germany.
I have not found anyone in my direct family tree using that spelling, but I have found some suspected distant relatives.The "distant family" I am in touch with in Poland say the oldest spelling was Iwitzki, but I have found quite a few variants in the US.I recently got access to the Chicago City directories from 1870-1923.
I found an entry for an Apolina Iwinska (female form of name)in the 1894 listing, Josie (widow of Henry) Iwinska in 1896, later listed as Josephine Iwinski in 1898, Albert Iwinska in 1902, later Albert, Martha and Walter Iwinski in 1906.
Albert, Martha, Joseph (machinist)and Walter Iwinski in 1908 Albert, Cazimer, Joe (machinist) and Martin Iwinski in 1910 Albert, Joe (molder), Martin and Samuel Iwinski in 1912 Alex, Joe (laborer), another Joe (Laborer), Louis and Walter Iwinski and Joe (Notary) Iwinsky in 1914.
I also found quite a few entries for Iwanski, a likely variant.I suspect a connection to the Iwicki tree, but don't have anything real solid yet.
I only searched the directory in even numbered years.Not all of the paper copies I made captured the info on Iwinski.
Do you know where in Poland your roots trace from?I have contacts there who can trace the Iwicki tree back to the early 1700s and the family story back to the 14th century.I just made contact with another iwicki in Poland who has family tree info back to the 1300's.He said there was a manor (town) named iwiczna.It was a manor in great poland /posnania, near kruszwica. In the 16th-19th century in east poland - lithuania.
There may be a common link when you reach back to Poland.