We have not done a lot of testing with the X4S other than to check that things nominally worked. The version that is currently released does not explicitly support the X4S anyway but we did just submit a new release with X4S support and it had no changes in this respect.
The P4P is collecting imagery in Map Pilot at 5472 × 3648 (just verified from uploaded samples). We have no X4S jobs posted yet and you don't have an account that we can find.
Until we get it fixed you can use more across track overlap that you normally would.