Hi and thanks for the great forum.

I apologize for some noobness of this question- It may well be simple but..... then again

I am working on creating some HDR pano's and typically shoot on a sunny day with some decent cloud overcast for contrast.

Shooting in full manual mode and striving for a 3 bracketed exposure of -2, 0, +2 I typically lock aperture at F8 with ISO 100 and then adjust the shutter speed as needed. For instance 1/250 for normal exposure and then 1/60 and 1/1000 keeping consistent through all the bracketed sets of the pano.

I apologize for a lengthy intro but here is my question:

How do I determine the best shutter speed for the panoramic as a whole? Do I base it on the brightest point (sun) and adjust or rather the darkest point or somewhere in between?
I did do a test the other day using the sun as the reference point with shutter speed at 1/500 and then continued on through with 1/125 and 1/2000 - the next set was done at 1/60 with 1/15 and 1/250 as the spread.
Is there a difference or has someone a trick of the trade for optimal starting point?

Again thank you!