I decided to use that length end loop, knowing the soft leather will stretch and conform over time. I placed a final prototype on a 1266 on my desk on a stand (hanging on the headband), and measured the amount of stretch day by day. One day to the next it would drop down a bit, then I would pull open the top frame some more to stretch it, and next day it would drop a bit more, until the leather reached its endpoint of stretch. Chose the end ring length going from that final point. Understood though that when new it's not the same as the well healed one you just removed. Bit of a catch 22. Sort of like a new shoe, it has to break-in.
The way it's assembled is for comfort, when worn it has more of a curved hammock shape rather than flat, better at spreading weight over the top of your head. What surprises me is the initial quality assessment, imo placing the 2 side by side there's no comparison, the new headband is far higher quality (just ask a woman).
I get it though, we all have our 1266 set, and now it's reset. Maybe replacement headbands should be one size larger (amounts to 0.05"/1.2 mm longer). Tiny changes length make a big difference in how it hangs.
