As well as the amount of vigour I think a lot depends on the rapidity of the strokes. The teachers from whom I got canings at school used to apply the strokes in quick succession, the first one had a numbing effect on the ones that followed. I don’t think the teachers realized that, fortunately.
I am mystified that people know the measurements of the cane that they received when at school. All I know is that if you were caned in the first three years it was a thin cane that left a considerable sting. When you were caned 4th year upwards then it was a thicker cane that left you in pain rather than stinging. If prior to the 4th year, you were caned in the upper school you found out sooner what the pain felt like