I have paused my progress with this mod so far. No time to play and i am waiting for that update thing that moder is doing. It's not clear if old chars be compatible after update so i am waiting at the moment.
For tomes - put them in cube. Transmute once - you get the same tome back with -1 skill level. Downgrade as many times as needed till you reach your char's lvl. I think this is broken thing because you can run nithlakh chest many times and downgrade/sell tome until skills maxed.