I took a few more measurements with different equipment.
The driver impedance is very flat. I've only ever measured typical moving coil drivers, so it's interesting to see how planar magnetic drivers behave. The impedances are within a 6% tolerance of nominal 18-ohm impedance, and within a 3% tolerance of each other. Not too shabby.
This next measurement is done with a CrySound 6151. I don't know how well it measures absolute curves. It's mainly for finding inconsistencies in driver performance in a production line setting. It's not like using the Audio Precision headphone test fixture that's lab-calibrated and a fairly consistent test setup that many people can use as a point of reference. Maybe the information is useful for some, though my frequency response plot using a measurement microphone from the last page of posts might be a more appropriate representation. That frequency response used 200 averages, where this graph is a single sweep without any averaging. The curves can change quite drastically based on position of the headphones relative to the artificial ears.
It's a bummer to see the absolute polarity is incorrect. Positive transients cause the drivers to deflect away from the ears. Maybe try a polarity flip on your audio output and see if one feels better to you while listening.
Ear cup outer diameter = 98.5 mm (it's a circle)
Ear cup depth without pad = 21 mm
Pad depth = 21 mm
Pad outer diameter = 100 mm (basically a circle)
Head band width = 25 mm
Head band thickness with padding = 8 mm
Height from bottom of ear cup to top of head band = ~200 mm
Width from L ear cup hinge to R ear cup hinge = ~195 mm