You might be surprised how accurate the KSG is when you use rifled slugs. Check out the Hickok 45 videos on YouTube:
I had my son's EoTech on mine, but it is awfully big. So I switched to my much smaller Bushnell TRS-25 red dot with a medium rise quick release spacer. I use Magpul back up sights which cowitness great through the red dot. I just added a pachmayr decelerator slip-on recoil pad (sz small) but have not shot it with the new pad yet. Without it, the KSG kicks hard when slugs are used.