I know I'm the same way... I may start with someone's recipe, but by the time I've made it a few times its miles from where I started. I love the spreadsheet idea. I have a huge three ring binder full of sheets I've printed off the internet that all have hand scribbled notes written all over the margins, and then crossed out and new changes added. Its getting damn hard to figure out what to follow anymore..
I'm just getting into curing more complex meats (I've done ham, bacon, and Canadian bacon along with some other simple brines) and I got this book hoping to learn more about the general processes and science behind how it all works.