this is a great mod that adds the exact major feature that is missing from the main game. There are so many one time only scenes that are a pain to dig through dozens of saves for without this in your playthrough.
oh and also note that this mod works fine with "Four Elements Trainer - Lain's Walkthrough + Gallery + Cheat Mod [v0.8]" the only thing to note is that it overrides Lain's mods Gallary on the main menu.
to get access to Lain's mod gallery you have to start the game and enter it there however it is kind of pointless to do that seeing as the gallery mods Gallary has way more content and a better UI, for the most part, the only thing that its missing that is in Lain's mod is the ability to alter your characters face in the 2 book scenes but seeing as that only affects your face in the text bubble it doesn't matter.
to tell the difference between the two mod gallery the gallery mods gallery is called "Gallery" and lain's mod gallery is called "Scene Gallery"
i do suggest that you install Four Elements Trainer - Lain's Walkthrough + Gallery + Cheat Mod [v0.8] as it enables cheats in the first two books of this game and also includes a walkthrough