Hi byacey;
Welcome to the forum.
I don't have that book handy right now so I haven't reviewed his recipe. I like to keep the salt content around 2%. If you use 2% that would be 2.8 oz. (or 18 grams per 1,000 grams of meat). Your salt amount is much lower, than I use. so I don't know why your sausage is so salty. Or is that the amount you are planning to use. Using less salt is alright, but it does impact the flavor.
You cure is a little high, and it should be .40 oz (11 grams), but that wouldn't make your sausage salty. Are you weighing your salt, or using volume, then converting to weight?