I've kill a lot of deer with buckshot from a 20 to a 12 3", from ten feet to 90 yards over 25 years. My advice on it is to avoid it unless absolutely the only option. Regardless of what yer "testing patterns" look like hold yer shots to under 40 yards. Last time I hunted with buckshot I shot and lost TWO big bucks in two days, both at about 40 yards. I found both of them later on, one a week later and the other in turkey season.
I'll bet the hit and lost % with buckshot is 10X that with a rifle.
I don't think we lose many. We do already have dogs on them though. I wouldn't use it if I wasn't running dogs.