How many pounds of pork trim will a pig's head yield?

[clubchuck]

I am working with a old family recipe that’s called Breakfast Liver Sausage.
The recipe starts with 4 pig heads that need to be cooked down and trimmed out.
I would prefer to substitute pork picnics but I’m not sure how many pounds is equal to trim from 4 heads. Any advise from the Walton’s community would be appreciated.

[bhaataja]

clubchuck I just found a recipe for the pig’s head I have in my freezer and the recipe said that the head will yield 3 to 4 pounds of useable meat.

[clubchuck]

Thank you bhaataja, I would have guessed closer to 6 or 7 so I’m glad I asked!