This Southern California lady isn't really qualified to help you, but when I want more figs, I pinch at 5 leaves. It appears I have a tree some members would like cuttings from, and it's destined to grow huge. This year, I am pinching for sprouts to make into cuttings to send next year.
Maybe you should take more cuttings so you can insulate those trees with hay or whatever you guys in cold climates do. Member's here may love your cuttings, and if they are gonna die back anyway, why not?
Good luck with your figs!
Suzi