I contacted HiFiMan about the fit issue with the HE560 v2 and received a Sundara headband in the mail this week. It still had the same size leather strap as the one that came in my box from Adorama so it was essentially a color change.
I took matters into my own hands and ordered a 10 dollar headband pad designed for Bose QC35s from Amazon that fits perfectly between the two plastic pieces and did a bit of DIY work on the Sundara headband by removing the leather parts after dissasembaling the plastic parts. I didn’t reassemble the right side perfectly so the yoke slider mechanism is a bit loose but it doesn’t actually slip when on my head so I have not bothered to redo it yet.
I’m calling this my HE560 v2 big head mod. I was on notch 6 or 7 with leather band on, now I’m on notch 0 or 1. With the black and silver Sundara headband I now have a nice black and silver color combo.
On my head it is comfortable even with how thin the headband pad is because the headphones are not that heavy and the there is plenty of contact surface to distribute the weight along with the clamp force that puts a lot of it on the side of your head.
I would put this behind my TH900s and K7XX for comfort and better than my Elears and 58X which are on the tight side for my head. It could be even more comfortable with a bigger headband pad but I love the look of this one and its not painful with my use so far.