I think you are gonna like your sausage, sounds like a good mix. The 10lb deer meat and 2 to 3 pound beef fat makes excellent hamburger... Try it sometime, it has a good flavor and you don't have to drain a bunch of grease off it.

I shot a doe yesterday, gonna run about 20lbs next week!

What I have done is gone to local butchers and asked for their pork/beef trimmings depending on what I am wanting to make. The trimmings the best in my opinion because they have chunks of meat left on the fat. Dont need as much of the pork when going this route as it is mostly fat.

'Bacon ends&pieces ' is the way to go for breakfast sausage (instead of 'beef fat' or 'pork butt').
Can spice many different ways; I do two (red peppers/hot, and black peppers mild).
Try it once, you'll never do it any other way. Butchers and even Walmart carries it.

venison & whole chuck roast (plus 5% bacon ends/pieces) makes outstanding burgers.
venison & pork-butt (+ spices) makes great italian sausage/ground for italian dishes.

The processor I used, Kurt Pickens 'tween Centerville and Oakwood asked me how much fat to add to the venison burger grind and what flavor. I went with 20% beef fat as the base to work from, as all this batch will be used for burgers, chili, meat loaf and pasta dish's with other spices added to taste.

Hope to get another critter and will do it in roasts, back strap fillets, stew chunks and any ground meat will get pork fat added this time and made up in breakfast patties. Had a 2nd hunt scheduled for last week, but BinL is having medical problems and I'm hunting on his land & lease when he is available.
Ron