Those really look good. When you used the old panels as the mold, it sounds like you just squeegee'd the filler flush with the surface of the panels? It looks like the edges are rounded which you wouldn't get from a squeegee technique - maybe you sanded that round detail later? Did the sanding take place while they were still in the "mold panels"? The depth of the panel groove is rather shallow, how fragile are they removing them from the "mold panel", sanding and painting, and then transfering the new panel?
Again, some close up pictures would be good, especially the ends at the panel edges.
-larry