I did this too when riding my ‘step-up’ horse and trying to get the hang of a bigger canter. I also found it helpful to pretend the pole/cavaletti was the size of the fence I was schooling - so I’d literally ride down to it like it was 3 ft or 3’3. I did that in all my canter flatwork too, just asked myself “could I jump 3 ft out of this canter right now?” If the answer was no, I needed more canter.
Tricking myself a little bit definitely helped me produce the right canter rather than just cruise around with zero impulsion and feel like I was accomplishing something, haha.