Create Montage with large overlapping


I’m trying to create mosaics with TrakEM2 software, connecting images of sciatic nerve axons at 37,000 magnification. I’ve done this through rigid since when I place the images in place of overlap there are areas with focus and others without focus. The question is if there is a command be given that there is no schema of the photos in the overlap area?
I already made one mosaic consisting of 8 pictures and after the montage is ready, I still get cropped areas. Attached Photo.