That DLSite page you linked was for Vol 4, no screenshots were added to the threads opening post but the game was.
Save files are just in the game folder, order it by name it's right by the exe. The bigger .sav is your game saves, the smaller settings. For the 2.5.2 game currently in the opening there's a voice mod
here.
You might want to make yourself with a copy of the game with tfpatchguy's patch mods though, its voice mod is better. Look back
here for 2.5.2, or
here for 3.0.22. But you can't swap saves between the game versions.
Edit - A bad mistype...