In the poem "Old Walt" by Langston Hughes, the author describes, in a rhythmic fashion, the manner in which Walt Whitman worked before creating each piece of his great expanse of prose and verse.
Hughes explains the process as a "seeking" and "finding" as Whitman starts with a question and looks for the answer or answers to that question.
"Finding less than sought" infers that Whitman had more questions than he found answers for.
"Every detail minding" indicates that the information he collected always moved towards finding an answer, and that the poet paid close attention to the details, never swerving from the truth of those pieces of information, but continuing with what he found, the process of "seeking and finding."
"Pleasured equally in seeking as in finding" means that for Whitman, the search brought as much satisfaction to him as finding the answer.