I especially like the ROR Tridents you've got going, a few years of branch refinement and they will become show stoppers. Wish I could get my hands on stock like this, a real credit to your growing/development skills

A very good question Gavin and I cannot give you a definitive answer - yet. Note a recent reply from assistant curator NBPCA thatSome imaginative trunks there, particularly in the ROR lot. How will you get the low half of no.2 to thicken, while you hold back the top? Can you get low back-budding for sacrifice branches?
but not sure that is the answer here. Excess (sacrifice) barnching has, in this case, contributed to the problem instead of solving it.You can still achieve gradual taper when growing trunklines or apex fast. The careful use of sacrifice branching in the area that you need more girth will help you out.