I don't know about the 30/70% "rule", Cheryl. Generally speaking, every time I cut my old fiddle (I didn't just cut, I air-layered and then cut after rooting), branching would occur at that cut. Not every time, but often. I air-layered branches that I wanted to reduce by 1.5-2', and the tree was around 7.5' tall. I air-layered that 25 yr. old tree twice a year, getting 15-20 new plants each year. I kept this tree at around 6-7' tall simply because I had to move her inside every fall and I couldn't get her through doors if I just let her grow.
Since your tree has numerous branches, cutting back the longest branches 3, 4 or even 5' will still leave you with leaf-laden branches, right?
