Size x Skill: Measure creature size, subtract size damage taken. Gain that many Bennies, of the same die type as the creature's skill.
CP: Measure creature size, multiply with structure level, add half of move, add size (for mind), add any specialties. Gain that many Benny points.
EDIT: There's also this. If you sacrifice the Size 4 biological horror, but it's already taken 3 size damage, should you get the full number of Benny points from it?
Remus: Harry... I'm a werewolf.
Harry: Are you fucking serious?
Remus: Well yes, but I don't see how that applies here.