I usually prefer -3/5 to emphasize this. I wouldn't call it an anti-slavery measure but one of a long series of compromises on the issue of slavery. Considerin

I usually prefer -3/5 to emphasize this. I wouldn't call it an anti-slavery measure but one of a long series of compromises on the issue of slavery. Considering 3/5 > ((0 + 1)/2) it seems to be a compromise tilted towards the pro slavery side.