allowing PCs to choose not to take spellbooks when the default sovs always take them is really inconsistent. either not taking a spellbook is too potentially gamebreaking, in which case everyone should always have them all and the option should be removed, or it's a useful strategy, in which case the AI should not take some as well.
i'm more inclined towards the former. in fact i think that starting inventory should be completely removed from character creation. with spellbooks it's completely stupid not to take them all (unless you like re-generating maps over again, which is an exploit and should not be encouraged), and with inventory it's almost always a waste of points in comparison to abilities that last for the entire game.
i don't think it's worth the extra customization when you think of the potential trap for new players. if you want to keep starting inventory, it needs to be completely rethought.
my two cents.