A general rule is 80/20, but that is for a lean meat such as venison. If you're able to get the fat out of the bear meat, I would shoot for that, otherwise you may need to cut back on the pork. The pork is usually added for the fat flavor, even though it's not all fat. I don't imagine the bear fat would taste that good, but you never know. Cook some up and if it don't taste bad you can work from there.