When doing a mosaic, after running AutoIntegrate script I often do just HistogramTransform at Pixinsight. With HistogramTransform I just try to get the panels visually close enough. Then I save panels as 16 bit TIFF and move to Photoshop.
In Photoshop I load the panels as layers (File/Scripts/Load Files into Stack…). Then I align them using a Difference blending mode (select all layers and change to Difference mode). It makes it quite easy to adjust panels correctly. After that I change blending mode back to normal. At this point it is still possible to adjust individual panels to make them match more closely.
I blend layers together using Edit/Auto-Blend Layers. Usually it works very well and you get a nice blended image. After that you can flatten the image and continue processing as a single image.