I've just done a couple of stitches. 3 frames from a 24 tilt shift, and 3 from a 45. Initial tonal and white balance tweaks in Lightroom, then into Photomerge on auto, then saved as a tiff/zip.
As far as I can see Photomerge is superb even though the 3 lens shifted files should be relatively easy to join. I would imagine things do differ with proper panorama stitching.
Once again thanks to all.
Cheers
Richard