So I'm looking for and HD shotgun and will ultimately want a trap/skeet shotgun. I was looking at the 930 combo 18.5" & 28" VR. My question is, what is the utility of the sights on the SPX version? Is it mainly for shooting slugs? B/C it seems to me everything else would be fine with just a bead at shotgun distances. I ask b/c the 18.5/28 combo comes with just a bead.