Thanks for the comments. I too have grown to like the lone figure, but only after desaturating the color from his fluorescent red shirt. I didn't have much problem with low light probably because it was very sunny during our trip because the 5dmkii does well in low light conditions. I did travel for the first time with a Benro tripod I got on B&H.
Here is one more pano from the interior of St. Peters:
It is made up of 6 images (2x3) and has a couple of obvious stitching errors in the column just to the left of center. This is image was stitched in photoshop because I could not get better results from PTA. I suspect user error.
Even with the stiching errors, I like this image (especially the shaft of light coming through the dome at the top left) and use it as my desktop.
Lastly, here is a painting from 1731 with about the same view: