I'm here late. All I can say is thank you for putting the link in your edit! I've been looking to crosspost my fic here from AO3 as an additional backup, but I've got one that's already 32 chapters long and will probably be somewhere over 50 by the time it's done. So I definitely feel your pain when it comes to posting multi-chapter fic to DW! I've been at a loss as far as organization goes, but I think that link's a great place to start.