I have found that I get a very superior result by batching the full sized images through a software program ProDRENALIN V1. that does a very good lens correction using their preset algorithm.
I then bring them into PIX4D desktop and process as normal.
To further refine I do a cell edit as needed in the Mosaic Editor, or reset the mesh to build from the Planar images. You may have to bring in a CSV file of the photo centres.
The lens correction filter in Photoshop or Lightroom does a less robust fix.