Truth many whom reported early eye strain seems to be more related to eye symetry not being equal.
If you look over pitool release 121 Beta introduces soft ipd adjustment (released last Friday). There is a recent topic on the new features for setting ipd & stereo overlap.
Standard gen1 headsets also cause some to experience Eyestrain; just like Pimax Wide FoV headsets do not for the Majority of users. (So all headsets are defective in that analogy)
My ipd is 67.1 and have no eyestrain your ipd should be fine.
With this being your first VR headset though you will want to weigh costs as with a Pimax headset you will want a beefy pc run it at a decent level of quality depending on content you want to run.