Overall, I would say it works, and it well spec'ed, though I will see these as goals, rather than specs.
I would have a bit of hesitation guaranteeing something that is so remote from the initial assessor. Ability to reach some of the tips would mean possibly needing more advanced climbing or a lift than might be able to be seen from the ground. If it is a per-hour job with an unlimited budget, it would be easy. How would you word the work order for priorities within a time-frame or budget?
I had a badly beaten sycamore that was majorly ice damaged. I reduced to to laterals and buds. It took a LOT longer that I thought, in part because of doing it spurless (as normal) and having pick-up sticks of big hangers in the tree near the roof-line. Oh, and seeing a cracked lead over the neighbor kids play-set which I could never see from the ground, too. Many/ most tree co's would say cut it down. HOs wanted to save. HOs then didn't put aside any money for the longer term management of the tree after probably coming in at half or a quarter of removal costs. I suppose I should have put specifically on the work order what follow up work should be, and a timetable.
How can you say 15-20% when you have non-elective pruning to do? If its cracked wood, it goes, largely, right. The sycamore had 30-50% crown loss, so I pruned as lightly as was reasonable for safety (see kids playset), being mindful of the large storm caused bud loss.