One of the difficulties in researching the SHEETS, SHEETZ, SCHEETZ, SHEATS, etc. surname is the variety of ways in which the name can be spelled. Standard spellings did not begin in the US until the mid to late 1800s, and many of us have found variations of the spelling into the 20th century. In addition, the surname, even when spelled consistently or "correctly", can easily be confused with other similar surnames.
It is believed that the "original" name of those of us in the US who claim German ancestry but now carry more anglicized versions was Schutz (with an umlaut) or Schuetz.
This is a list of spelling variations that I have discovered in my research. Those that seem to be the most common are noted with an asterisk (*). If anyone has any additions to this list, or other comments, please let me know.
The following do not appear to be real surnames, but are examples of how I have found my ancestors' name mispelled in modern indexes:
SHRETTS (1850 census; census taker actually spelled it Sheetts)
SHETYS (1810 census; census taker actually spelled it Shetz)
The following are different, presumably unrelated, surnames which I have seen confused both by original scribes and more modern indexers with our name:
Hope this helps; when the list is "finalized" with your help, I intend to print it out and post by my computer and in the binder I take with me on research trips, as Soundex searches are not always available or helpful.