Converting a recipe (downsizing it) for modeling chocolate?

I found a recipe that takes 1 lb of chocolate and add 1/3 corn syrup to it. If I want to only do 4 oz instead of 16, what would be the conversion down to that for the corn syrup? Is there a site anyone uses to get calculations like that? I’ve found site that convert it to other measurements, but haven’t found one that divides it down equally.