You could also do it modulo some number, I think?
Then knowing any individual number (weight + pad) mod n gives zero knowledge (I think. If all but one party reveal their pads, they can trivially determine the other's weight so it fails. Believe it to be secure if only 1 party is malicious, though. Cases for other numbers of bad actors are more complicated...)
Then you would probably get more information from looking at the person thank you could from hearing a weight number that could be +/-2000 pounds