As a slug gun hunter A group of use git together to see whats works and what does not. We do all see one thang thats does not change . Slug are as picky as .22lrs about what they like best even from the same high end makes like benelli. I have a mossy with a 24" slug barrels. All our slug guns are scoped. The one round they all shoot well enought is remington buck hammer. Shorter range round as it slower to start with and the larger flat front surface doe not help that but it does seem to be the best shooter consistantly. with 100 yard groups of 4" being practical. With sabots??!!. I use a hornady sabot , 1700fps 300 gr sst bullet . Good for 2 1/2 to 3" 100 yard groups for me. Better for one guys benelli worse in another. But with the right sabot 200 yard heart lung shots are very practical.
You just got to try some.
Buck shot? I reather use 1 buck down to T shot. Higher pellet count and pellet size and after growing up as a buck shot hunter killed way to many deer with 1 buck. If you own a screw in choke tube barrel the 1 buck in general holds a better pattern as the chock tightens up at longer dostance as with a full choke. O and OO buck tends to spread out thru a full chock tube as distance increases. 1 buck of the right make and lenght for your gun can be very diedly beyound 80yards. For home defence. T shot-.20cal, and 4 buck-.24cal, might be best as you still most aim your shotgun at short in house distance and do less damage as it passes thru walls.
To many test are restricked to only a few, very few shots sizes, and slugs/ sabot brands . No sabot is the best for defence . grab a rifle then.