It seems like most of the issues people experience when first using a Pimax headset are related to IPD and eye depth not being properly accounted for. The eye tracker should be able to measure both.
The Tobii eye tracker is able to measure eye relief (distance from the tracker to the eye). The 7Invensum tracker should hopefully be able to do the same. Once you have that it’s fairly simple to calculate other distances since they are fixed relative to the tracker. Then you can implement one of the following:
Preferred - Automatically adjust the distortion algorithm based on the eye depth
OK - Include a tool in PiTool that lists current eye depth and an optimal eye depth for the current distortion algorith. Then the user can adust accordingly (ie adding/removing foam or velcro spacers).
Once the eye depth is properly accounted for, then you can measure the user’s physical IPD and recommend what value they should move the physical IPD slider and/or SW offset to.
Also note that eye tracker may need to be recalibrated after some of these steps.