In reading over Carl B. Smith, No Longer Jews: The Search for Gnostic Origins, pp. 237-44, it is apparent that manuscripts have a real part to play in mapping the origins of the early Christian movement. Walter Bauer argued that gnostic Christianity preceded orthodox Christianity in Egypt. Apart from the fact that we have very scant evidence for any Christians in Egypt in the first century (be they gnostic or orthodox), Colins Roberts ("Early Christianity in Egypt: Three Notes," JEA 40 : 92-96) identified 14 papyri that could be dated to the second century CE in middle and upper Egypt. These texts were "orthodox" and showed signs of Jewish influences, and only two have gnostic tendencies:
7 OT texts
3 NT texts (John; Matthew; Titus)
4 Extrabiblical texts (Egerton Gospel; Shepherd of Hermas; Gospel of Thomas, and Irenaeus' Against Heresies).
Brook Pearson adds to the list several other non-gnostic manuscripts:
Gospel of the Hebrews
Gospel of the Egyptians
The Secret Gospel of Mark [though I doubt this existed]
The Epistle of Barnabas
Does the textual evidence count against Bauer's thesis (at least in Egypt)? See further Smith, No Longer Jews, p. 243.
What further role can analysis of manuscripts play in plotting the various parties, groupings and overall diversity of early Christianity? Or is this line of evidence itself suspect due to our inability to assign a provenance to any manuscript with complete certainty?