I don't think the OP is still waiting on a reply, but older saves can be moved to a subfolder, etc, and while the manual saves follow a naming convention, saves can be renamed without issue (I've only tried adding things, like savegame01-levelX.dxg).
The easiest way to get to the save folder would probably be to copy the following into the location bar in Windows Explorer.
%LocalAppData%\Divinity 2\Savegames
Congratulations on the post number, I guess.
I got 667... neighbour of the beast.
