Just get Vive DAS and attach it as MRTV recommend, but not use the vive holder on the top. I use hard paper to make the holder because the strap is too wide.
Although I use the small fov, I still can see the distortion because the face pad is too thin (11.5 mm.) and the DAS is too fit. Try to use vr cover face pad (16 mm.), distortion look worse. So I think 13 mm. may is better.
The headset is good when I want to lay my head to the chair while I can’t do by mixed reality headset because it has too thickness. I hope pimax will consider about this too.
p.s. I solve issue by add more foam at the back.
After I test with my son (4 years old), this is too loose and I need to use vr cover instead (16 mm., but I can’t use this because distortion).
And need to paste more velcro at the behide like vive pro vr cover.
vive, thicker version.