…finished!
That is, tonight I finished reading the last to chapters and marking tweak-like edits, typing the edits in the last four chapters, and merging all the files into one file, and formatting that. Thus my fourth round of edits is over, and the manuscript is ready to submit in full, should anyone be interested. I still have a few formatting issues, such as adjusting some paragraph indents, but it is presentable as it is now.
Of course, I don’t rule out another round of edits, should I feel led to do so or should it be needed to make it acceptable for publication, but now I can put this aside, and concentrate on other things while the agent is considering it. I don’t think I’ll do any research into other agents right now.