You don’t need an ebook (unless you want to learn chemistry, then get a chemistey book) and you certainly only need a patent if you want to make sure that you don’t commit patent infringement.
Using HCl is a very simple procedure and results in a brownish soup which smells of bouillon.
Using enzymes is a cleaner way but you might struggle finding suitable enzymes at a suitable price (especially if you’re not able to recycle the enzymes). Every enzyme requires its own reaction conditions; a supplier might help you out with that but you’d still be forced to do your own trial and error adjustments.
Don’t forget that pre-treatment of wool can greatyl affect the outcome of an enzymatic digestin. You might find tips and tricks on Sciencedirect or PubMed.