I believe elms where what was referenced (or some other deciduous tree) I did find a video where someone showed the technique on pine though. I can see how that spiral pattern never really goes away after seeing that. I value my little pines too much to mess with them in that way. My pines are a whole new frontier for me so I’m happy with just keeping them alive. I have heard of the spiral cutting as well but I can’t really wrap my head around how that works. I guess I need more of an education in the physiology of the species I’m working with.
The best way, or rather, the fastest way to fatten any trunk is to plant it in the ground, and let a sacrifice grow tall.
If you want taper, the sacrifice trunk will have to be cut, and a new leader be allowed to grow tall. This leader will subsequently be cut, and a new one trained to take its place.
Of course, each time the sacrifice trunk is cut, there is a scar. Scars heal best when there is a strong apical leader growing above it.
The key to success is managing the growing, the cutting back, and not letting the sacrifice branch get so big that the scars won’t cover over.
And time.
By the way, anyone can post bad techniques on this or any other website. And, they can post good techniques. It’s difficult to separate the wheat from the chaffe.
By my stating that you don’t find any good examples, or corroboration, i’m giving you a clue that you’ve stumbled upon misinformation.