Edmund,
Your first attempt of a mosaïc is quiet impressive, the panels have the same levels an everyting is pingpoint, really nice! 8)
The only thing that could be changed IMHO, would be to more restrictively proceed with the DBE tool, perhaps a SCNR to supress some greenish touch an finally a manual Histogram stretch to "calm down"
the background, these applied to the finished merge..
Edmund, great Job on a 9 panel mosaïc, what is really not easy game!