agree w/ rg, shoot for 30% pork fat, i might even just round up to a 33%pork fat: 66% venison, don't grind the venison too much.
to make a basic venison kielbasa, use 3-5 ounces of fresh garlic(one bulb yields about one ounce of fresh garlic), 25# venison, 8.66# pork fat, .33oz. marjoram, .33 oz whole mustard seed, 7oz. salt, 24 oz cold water.
chop up garlic, add garlic, marjoram, mustard seed, salt, h2o, to meat and fat, mix well, you need a big enough bin to mix this amount of meat, i would mix this by hand for a good 5 minutes, make sur it is mixed thoruoghly, don't be afraid to add more water, it will help to incorporate all the ingredients and the hand mixing is gentle enough to form protein bonds while not emulsifying the meat and fat, go buy some good plastic gloves, good luck. what i might do if this is your first try, is to start out w/ a first batch of 6.25 #, weigh everything out, record it in a book, see how it turns out, make tweeks or your good, double recipe to 12.5#, or triple to 25#, good luck.