Do you know anyone with a .32 H&R or .32 S&W revolver? Shoot a 60 - 80 gr. cast lead bullet with a muzzle velocity of 1100 f/s or so, into whatever test medium you have handy, set out at 40 yards. It should give you a reasonable "first approximation" as to how 00 or 000 buck should behave.
Actual buckshot, fired from an actual shotgun, will (PROBABLY) have a higher muzzle velocity, though it may not retain it as well as the pistol projectiles will. It's not a PERFECTLY valid comparison, but it might tell you what you're wanting to find out.
At 40 yards, I'm not optimistic about getting all or most of the buckshot pattern to hit the penetration medium (unless it has a very large frontal area), so it's difficult to say how different a a salvo of .32 caliber lead balls might behave vs. a single .32 caliber wadcutter or LRN. Doubtless, the former will incapacitate a target faster than a single round if delivered anywhere but the brain.