This is related to a previous question of mine: Convergent, parallel plotlines okay?. It has been suggested that this is might be too closely related to that question, however whereas that question was my concern that I was falling into some over-plotting pit fall, this question is about my implementation.
First I'll explain the situation. I have a story with three plot-lines (A, B, and C) with their own cast, settings, and conflict. Meanwhile there is also an over arcing conflict which reveals itself as the story progresses. Eventually, in the middle, the three plot-lines converge in twos (first B vs C then C vs A) before diverging again. In the second half of the book they are all moving forward to the conclusion where the lines converge for a tragic ending.
The characters in A have only misleading information, and it is unrelated to the larger picture. Characters in B immediately---at the start of the book---know of this deception and are following the movements of characters in A. Characters in C also know what is going on. The characters in B and C do not share information with the reader for the sake of telling a more interesting story (they pretty much know everything). The information is slowly shown instead of told.
It was originally conceived that I would write short arcs---two to six chapters of 4-8k words focusing on one plot-line with their own short-lived conflict which is revealed and then resolved. Through these small conflicts we learn of the over arcing conflict as well as move the characters closer towards their confrontations. Before I write them I make sure each chapter and arc are advancing something central to the main plot, so these arcs aren't just subplots for the sake of subplots. With the exception of plot-line A, which is the protagonist's plot-lines, the characters in B and C will be acting and reacting with awareness to the other plot-lines.
After outlining and summarizing these arcs, I then arranged them in chronological order.
And therein lies the one problem. Some arcs can't be broken up in such a way as to allow this. One in particular B arc spans three other plot-lines' arcs, but with funny overlap so I can't absorb it into another arc. One solution is to completely scrap that arc and rework it so that it can be concluded and then restarted in the middle. This is imperfect, but doable.
Another problem is that I fear I might confuse the reader, or make it harder for them to connect to characters they might not see again for another 5 chapters. Personally, I would be intrigued as I think about how the information we're learning in one line impacts others, how the characters work in opposition to another, and how the protagonist is struggling onward as the unwitting tool of other. But that's me; I'm weird.
The previous solution I mentioned does not fix this.
Earlier today I was thinking about my favorite Sci-fi books, among them being Dan Simon's Hyperion duology. In the first book of his, he presents the tale in framed stories. Each of six tell their own tale as the over arcing plot moves on. The second book is then more the norm, and what I am going for currently. You have the pilgrims (plot A), Miriam (plot C), and Keats (plot B).
I'm not sure a framed story would work in my case, however I am considering writing out one plot in its entirety before moving on to another, writing each of out before moving on. I would then call that one book. Considering the projected length (which I always underestimate) this will be about 400k+ words when finished (before cutting). Even after cutting, its likely to be just shy of 300k words so breaking it into two books has its own advantages, and I do have a natural way of executing the divide.
The specific way I am considering arranging the first book is to write out plot B which has the most "reveals" or "plot bombs", then writing plot C which is both the antithesis to B, and the chief target of the reveals in B. Finally, I would write the plot A out, which is the protagonist's line. We see her struggle under false assumptions and also finally get to see the conclusion of the first book. The plan is that at the end of book 1 those in B arrive late, C arrives early, and A contains the protagonist who drives that particular cluster (her first show of real agency).
The question, then, is whether or not this is okay, or if I should find some other solution.
When I looked this up online, it seems as if the advice was to interleave the plots, however that is what I've been doing, and am not sure that is the best way to proceed. I've so far written up to what would be the middle of the first book (should I split them) and have outlined the rest of the first book and nearly all of the second (parts of the middle are missing), writing log-lines and summaries.