Of course the thickness of the cane did change with the age of the pupil but other considerations were taken into account, and in fact more important. If the cane was going to be used on the hand a much thinner and flexible cane was used than if it was going to be used on the buttocks. This was to reduce the risk of injury to the fingers and bruising to the hand. When using a cane on the buttocks a thicker cane was used if it was done over clothing. Canes used on the buttocks over clothing tended to be much more rigid so as to ,make a greater impact on the buttocks. Such canes were the ones that left the buttocks bruised often for three weeks and the boy feeling where he had been caned for several days. These canes landed with more of a THUMP sound than the whippy canes used on the hands.
Like myself, in spite of reservations about its use by many, a fair number of heads use to cane either on the pants or the bare buttocks. It is true that the later was most commonly used in private schools or in my case church schools run jointly with the local authorities, mainly prior to 1965. A few heads did prefer to cane on the pants or bare buttocks as the thinner whippy canes could be used. These landed with a THWACK sound. Such strokes would sting at the time more than the rigid canes, but did not leave the buttocks so bruised as the thicker canes used over clothing. These thin canes bent on contact with the buttocks, and with the boy not bending over so much, as trousers and pants did not need to be stretched so the buttocks were more relaxed and so would not cut or graze . this was the advantage of a thin whippy cane used on the buttocks