Glad you made it, Orson. You're certainly not alone in the time you spent on it. It took me a good day and a half.
It's easy for a setter with specialist knowledge to think that the internet will come to the rescue of solvers who are unfamiliar with his area of expertise. But with complex subjects such as this puzzles involves, lay solvers need to find something that really illuminates the subject so they understand what they are doing, and that's not always easy to find. Today I found a very clear Youtube demonstration of the use of Argand diagrams. If I'd found that two days ago I would have found the endgame far less frustrating.