Long reply, but I think worth the read...
The IWBA article referenced argues that #1 buckshot has a 30% increase in wound size over 00 buckshot. The specifics, though, are a 1.13 square inch shot pattern for #1 vs. a 0.77 square inch shot pattern for 00.
First, the practical difference between 0.77 inches and 1.13 inches at two to three yards is negligible (read: silly). By way of analogy, imagine two ballistic missiles. Missile A strikes within 3 feet of your house every time, whereas Missile B strikes within 100 feet of your house every time. If both missiles' payloads cause a crater 2,000 feet in diameter, then saying Missile A is more accurate is factually correct; however, if the crater you've made
exceeds the difference in accuracy between the two missiles, there's no point to the discussion. Your house would need new wallpaper either way.
Second, the IWBA's 30% increase in wound size is based on shot patterning. The problem, of course, is that shot patterning is not the same as a temporary stretch channel, a wound channel, or penetration. According to tests on ballistics gel, both #1 and 00 buckshots produce strikingly equal temporary stretch channels (at 8.5" each), and very similar wound channels. By wound channel, we mean, "What is the path of the pellet inside the human frame?" This is where the similarity between ballistics gel and humans fall short, because the variations of the human frame just aren't replicated in a block of gelatin, but you can reliably say that the two loads react similarly. Thus, the only difference left is in penetration, and in fact the penetration of 00-buckshot in ballistics gel is about 30% more than that of #1 buckshot. Of course, clothing, bones, and other variations of the human body may not allow exit of either shot in any case.
A visually dramatic analysis of shotgun rounds takes place at:
http://www.shotgunworld.com/bbs/viewtopic.php?t=109958
(WARNING: SITE NOT DIAL-UP FRIENDLY!)
The authors offer pictures of a huge variety of birdshot and buckshot embedded in ballistics gel. Though the authors' examination fails in not taking into account clothing, bone, and the differing structural density of human tissue, the
relative differences are still valid.
At any rate, I choose 3" magnum (15-pellet) 00-buckshot for home defense. A center mass blast on-target within home defense ranges would be similar to a 15-round simultaneous burst from a 38-caliber submachine gun. That would certainly fall within the range of the one-shot stop.
I appreciate the opportunity to share my opinions.