I hear ya!
Well shoulder butts would be a good start. Maybe 50/50 if you go that route. Whole hog, I've seen ratios down to 30% venison 70% pork, but each to their own. I was mainly getting at apples to apples. Obviously something like back fat would be less than picnic by example because of the fat to muscle ratio.
I would give it a good look and start at 50/50, if it looks like a good pork trim go 50/50, on the fat side maybe a little less or a bit more if it's lean. It's hard to give you a definitive answer, we professionals do it all by sight.
But usually 50V/50P is a really good rule of thumb like everyone states.
