This is a long post so bear with me.
I take the middle sheet from the last signature. I measure it against the template, I eyeball it because I find that works best in the finished book. Measuring it with a ruler can make it static and too stiff. I like an organic feel.
These 3 pictures are of the finished jig. After I mark all the stations on the jig I fold it back along the orginal fold, so that the marks are now on the inside of the fold. After that I punch the holes with my handy-dany home made awl. (A wodden dowel cut to my hand size, smoothedand rounded to comfort. A leather needle had the eye cut off and a small drill was used to drill a hol in the end of the dowel. I then glued it in place with gorilla glue.)
For me this method works best. I’ve cut my stations, I’ve measured each one. I’ve created mini jigs, etc. . But this has been the best for me. It’s also similar to what Keith Shith describes in one of his books. He uses a smaller jig, while I prefer to use an actual sheet from my book. Though I must say that when I work with images or words I make a jig that is seperate. It protects the pages from unintentional damage from the awl and dirty fingers.