I made 25lbs of elk snack sticks last month with about 17lbs of elk and 8lbs of butt using Hi Mountain's sweet & spicy (which, as it turns out, is neither very sweet or
spicy and I even added 2 tsp of crushed red pepper to it
I dried them overnight and smoked in the same temp increments that you did and then let cool at room temp.
Once they were cooled down I moved them to the fridge to chill and then vac'd them.
I'm wondering if you dried the casing too much and that's why you ended up with them being chewy. mine have a soft snap to them and the casing easily breaks down while chewing, as opposed to slim jims that always leave me with the feeling that I have a wad of pepperoni flavored paper in my mouth...
One thing is for sure, if you're not using a prepared snack stick recipe, add more pork.
Hi Country and Hi Mountain recipes have ingredients that hold moisture and so less pork is needed, if you're making your own spice blend (and probably not adding those ingredients), the sticks will turn out drier without the pork meat and fat.
Even with the ratio of pork that I used, the sticks are very meaty - not greasy at all.