You've done a fantastic job with these graphs mate, thanks! My XE800 sounds like a combination of the 2 year old's bass with the one year old's treble. Treble peaks aside, it's closer to reference but it sounds V shaped to my ears whereas the GR07 always sounded flat to me till around 4-5k. Still, what matters most is that they all share the same driver. You can easily eq the fr with a tone generator to make it sound flat to your ears, but speed, transient response, distortion and the like can't be improved and there is where the XE800/GR07 drivers excel.
I would only experiment with the back vent. It's further away from the driver so it's safer and it's the one that affects the bass:
If you don't like the result you can easily re-seal it so it should be a low risk test.