I usually supercrop the whole limb at one time and make the whole area I want affected turn soft and quite limp. I usually use it to slow limbs down when they are getting out of control. It also thickens and strengthens the limbs as they recover. Given that your plants are young and a little on the spindly side, I'd say just do a bit at a time and see how you like it. It's harder to supercrop a second time because the stems toughen up, but it can be done, just takes a bit more work. By then there's usually a new section above the super cropped area that is soft and ready to be squished as well. What are you doing the supercropping for- to strengthen the stems?