For 3.33 lbs or 10 lbs of meat, or multiples of those, the recipe is calibrated so most ingredients come out at an even tsp/tbsp figure. But you’ll be able to figure it out for any amount.
I recommend not more spice mix than you expect to use in a few months. Certainly not more than a year.
The meat side of the recipe calls for 50/50 venison/pork. That’s a loose guideline, based upon using fatty pork shoulder. If using fatback consider using 70/30 venison/pork. And in-between for pork shoulder trimmings.
But 100% venison is fine if you and your audience are OK with leaving out the flavor and texture that comes with the fat. For sausage patties or links the pork fat is more important. For breakfast tacos or burritos, 100% venison can be fine. It’s all a matter of taste.