Looking for Information on Manasseh's Captivity

I'm doing an in-depth study on the kings of Judah and Israel. I'm familiar with Thiele and Young, and I've read a great deal of literature on the subject up to present. Where I am at the moment is Hezekiah and Manasseh. Relative to the Assyrian chronicles for Shalmaneser V and Sennacherib, Hezekiah's reign is a mess. I don't accept Thiele's conclusion to move his reign in its entirety. But none of the known starting points for Hezekiah pan out. In order to date his reign, I'm trying to work backwards from Josiah. We know that Josiah died in 609. He was preceeded by Amon, who was preceeded by Manasseh. From Hezekiah to Josiah, there is a gap of five or six years that can't be accounted for. This gap cannot be overcome by a Tishri/Nisan counting difference, or by accession-year versus non-accession-year counting. It's just a gap with no explanation. My suspicion is that Manasseh's total reign is a cumulative total, not a sequential one. We know that Manasseh was taken captive, and that he suffered at the hands of the Assyrians/Babylonians badly enough that he came to a full state of humility and repentance. My suspicion is that his captivity lasted something to the extent of five or six years, which is what causes the sequential gap in the reigns from Hezekiah to Josiah. So, what I'm looking for are solid sources that might help pinpoint when Manasseh was taken captive, by which king, whether Sennacherib, Esarhaddon, or Ashurbanipal, and maybe even an event; a rebellion, or similar. Perhaps the event compared to the remaining years of the Assyrian king will help shine some light on his captivity.