I'd like to modify a long period of the memories of the target.
Is it possible? Can I do it better? What are the problems with this method?
timeline: Past-(Fake Past)-Present
The goal: Make the target think, that long fake past is real. Fake past does not contradict the past.
Wait till the target is asleep.
Cast Dream. During "8 hours" of the dream, I, as a Messenger, replicate the core events of Fake Past. ("The messenger can also shape the environment of the dream, creating landscapes, objects, and other images."). I cannot be 100% sure that the target will follow my plan, but let's assume this is not a problem.
The last segment of a dream would be the fake waking up and recalling the past events.
I cast Modify Memory to remove the memory about the real waking up.
I hope that "Its mind fills in any gaps in the details of your description" property of Modify Memory will help me, because I do not replicate all events during the dream. Only the core.
If it's not the case, I still can use my 8 hours of fake memory instead of 10 minutes. This is not months I hoped for, but good nonetheless.