I think their times when both parties are putting in the same amount of work, on those occasions the props should be split 50/50.
And then their other times when one person is breaking themselves to the max, i think in situations like that you should both no who deserves the kudo's.
"finally after you've busted, and you're pretty much outta breath, your smashee (who hasn't broke a sweat, nor barely moved) looks at you, and says "you ok? damn, i must've f***ed you good." now you're lookin at that bish sideways like "wtf!" - In situations like this the girl is either crazy or maybe just maybe you weren't as good as you though you were