These books should be all that you need to find satisfaction. Curses are only deflected by those who intentionally practice magick or other such spiritual techniques. The vast majority of people do not do this.
If magick did not work on those who are religious, it would be quite the disappointment. Vaguely praying to God is not going to stop a well crafted, mighty curse (though the target may be horrified to know that God may be empowering said curse). Follow the instructions in the books, do the magick, and then allow yourself to move on from your enemy as you witness their gradual, or perhaps quite rapid, destruction.
I do not know the details of your situation, but I am 99% sure that you can just perform the Master Curse, or the Lesser Ritual for Torment, or some combination of rituals in AoW, and you will get what you want. On the extremely, extremely slim chance that your target has magickal protection, which if they do not practice magick would be placed by one who does, then there are rituals in AoW which can remove that protection.
To answer your question, the ritual instructions have been crafted with beginners in-mind. I would consider Magickal Attack to be an introductory text, while Angels of Wrath is slightly more advanced.
The former provides you with a well-crafted template for an effective curse. All you must do is follow the instructions. The latter, however, requires you to construct a curse of your own, which requires more thought and expertise to be maximally effective, as well as confidence in your magickal abilities.
Repetition is sometimes included to ensure that the ritual is performed well at least once. If you make a mistake one day, or do not fully engage with your emotions in the ritual, you have several days to learn and practice. This also helps you let go of lust for result, which is the only problem that you may encounter. There is no need to worry about “weakening egregore protection” or anything of that nature when you use strong magick. Do the magick, trust that it will work, and get on with your life.