For what it is worth, I hunt with 3 buddies and we all use 12 Ga. H&R Ultra Slug guns. Our group hunts NJ, Delaware, and Maryland every year. Last year we accounted for 13 deer. In Maryland we hunt a farm that has a number of fields bordered by woods. I usually set my treestand up in the corner of this one particular field where some fairly long shots are possible, consequently, I use a Nikon Rangefinder when hunting that field. Last season I took a small 8 point at a ranged 154 yds. The buck dropped where it stood. My Ultra Slug gun prefers 3 inch Federal Hydra Shok sabot slugs but of our group, no two Ultra Slug guns prefer the same sabot slugs. You just have to try them all to see which your gun prefers. You should also add a LimbSaver recoil pad to your gun as those 3 inch sabots do kick a bit.
All four of us switched to 3x9 Nikon Slughunter scopes before last season. What great optics. I love the BDS reticule and the clarity.
Good luck with whichever slug gun you choose. There are a number of good ones out there. Just don't get hung-up on the need for multiple shots because after the first shot, the deer is usually either down or gone!