As mentioned in an earlier post, Warren Gentzel of Circleville, Oh is historian for the unit, and has some in depth information about many 90th soldiers and their families. Mr Gentzel is on the board of the Pickaway County Historical Society, and would be at least one place to start. He knew more of one of my ancestors than than my own family did. Hope he can offer something to assist in your search. cwgentz1@bright.net is his contact address.
Best of luck in your search,

Ray Moore