The minimum height quoted allows for the amount that can be easily cut from the base of each column or half column.

Smaller heights can be achieved by cutting up to a metre from the bottom of the shaft (before there is any change to the shape of the shaft). Please note however, that on a full shaft the under part at the bottom has a wider 'lip' to allow for good adhesion to the plinth. If you cut the shaft this 'lip' is cut away.

You will therefore need to attach a wooden block, or something similar, to the bottom of your cut shaft to allow for good adhesion to the plinth.