What does the collective GT shotgunners think are the better arrangements for sights? I'm serious in getting a dedicated defensive shotgun setup with the Mossberg 590a1 and 930spx as top runners. The 590 can be had with a bead or ghostring sights. I think the 930spx only has ghostring sights available. I think the bead might be faster, but then I think the ghostring would be beneficial with slugs. What say you?