Sup, FEFTwiddler guy here. I've been lurking this thread... don't tell anyone!
So I've played the game for like a couple hours so far... enough to get a save file. Figured I'd post some basic info to help you guys out.
The attached screenshot is a decompressed SoV save file.
If you look at the block starting at 000000C0, it has "INDE" followed by the points in the save file that each "region" starts at. So, for example, that "D1 5C" is the convoy location. It begins at 00005CD1, and ends at 00005E8E, where the next region begins.
If you change the size of the save file (e.g. by adding units or items), these values up here also need changed or weird stuff might happen when you load the save (due to the game looking in the wrong place for data).
To people looking to add/edit/delete units: I can't speak for this game, but in Fates, within the unit region, there were blocks for the following groups of units in Chapter saves:
* 00 xx - Deployed living units (only applicable on battle prep saves)
* 03 xx - Undeployed living units (this is all living units on non-battle prep saves)
* 04 xx - Dead units that died for gameplay reasons
* 05 xx - Units who left the party but will rejoin later (example: Kaze, Rinkah from before chapter 6)
* 06 xx - Dead units that died for plot reasons
* FF - End of unit region
In each of these examples, xx is the number of units in that block. It appears to be the same in SoV.
* 03 xx - Alm's army?
* Some other value xx - Celica's army?
I'll leave it to people who have already played the game to figure it out from there.
This is about all I can really say for now. Maybe I'll post more when I've played more of the game. Good luck in the meantime!