Glad that you did it, but here are some tips with the Evil Book strategy:
You may need to do an easy Catacombs spider stack or two to ensure that you get Level 5 Daert for the final stack whichever is tougher between the Elves and Humans to get more Mana (I actually had to do this in the Ball of Lightning strategy, too). It seems more likely than not that I end up a few exp short of level 5 and so I need to do at least one or two of the easy stacks in the Catacombs to push me over. You should be able to start with 36 Mana for the harder fight and with at least Level 1 Concentration you are no more than 4 rounds from your second Evil Book level 2. Level 2 Meditation is better than Level 2 Concentration and both cost 8 Magic Runes. Level 2 Meditation will get you 40 Mana. I was 2 Magic Runes short, however, in my Ball of Lightning playthrough when I got Daert to Level 5.
You also need to have 2 Evil Books @level 2 versus the Swordsmen / Guardsmen so ensure that your book stays away from them until you get that second Book because one level 2 Book is not good enough against both of them. It can handle a single troop, though, so place your Vamps' starting position to split them up (especially the humans) if you have to fight one to recharge your spell.
Both the Priests and Inquisitor's / Sprite's and Faun's damage is Magic (well half the Faun's anyway) and so try to get them to attack the book or if your book needs to reload its spell attack then attack them to recharge it.
In my test, I actually found the Human stack much easier than the Elven stack, but it just depends on how much they attack your Vamps versus your Books and the spells your Book casts. If it is casting Slow, for example, then use it on a fast troop. If it is casting Lightning then use it to cast on a troop for maximum damage, etc.
You also really need to have it be a damaging spell on its first cast, otherwise it gets way harder. A Poison Skull, Ghost Sword, Magic Axe, or Lightning works wonders on a first cast and this has to be cast on either the Elves or the Inquisitors. Position the starting location of your Vamps, change the time in the round when the spell is cast, etc. to get it to change if it is not good. Sequence of events is everything!
Lastly, remember the goal of your Evil Books for both stack types: 1) for Humans, once you get rid of the ranged troops, the fight is over and 2) for the Elves, once you get rid of the melee troops, the fight is over.
As a variant, you may decide to do 2 Points in Meditation and 1 in Concentration / Chaos so that you can do 3 Level 1 books (but in my experience this is not as good and requires 45 total Mana).
Anyway, glad you were able to do it!
/C\/C\