Waldo Street Pottery
Chumono
This is an issue. Harrington is working with a different species--Fagus Sylvatica. American beech --Fagus Grandifolia--isn't as vigorous.
Having grown both, I can say American beech isn't as amenable to bonsai culture as the Euro species. Grandifolia is not as responsive and will weaken over time with the same bonsai treatment. Proceed with aggressive treatment at your tree's risk. What works for five years, or even ten, might not work longer term, especially if you've worked the tree hard enough to get it into a decent bonsai container. I worked mine into a pot that was an inch deep. Did fine in that for a decade, then began to lose branching.
I removed terminal buds in the spring. and trim for silhouette too. Got decent backbudding, up until a point...
Duly noted and something to consider. My main tree is a cascade and will go in a deeper container this year, provided the pot gets fired and doesn’t crack?. That will give it a good bit of room. Maybe I give the Harry technique a year off too...