I've used this technique on (softwood) trees in the 2 ft, 100 ft tall range. This is an advanced technique, and you need to be proficient in reading the tree and watching its movements. Through the cut angles, all I'm doing is redirecting the weight, and once I get it shifted, I manipulate the lean, and the lean into swing once it gets into motion. 3/4 of the way into the tree on the first cut is minimum. Sometimes I only leave 2-3" of wood left on the back side. All depends on how I read the tr