I tend toward 3 blade with pigs. With the extra fat and shield, a little wider hole seems to help. With a wheelie bow and a 2 blade I nailed a nice boar several years ago. Within the first 10-15 yards there were the most amazing sprays of blood off to its right I've seen on any game I've killed with any weapon - I mean 2-3 feet wide. Then it stopped. I tracked that boar for over 400 yards (laser range finder measured) mostly by where it rubbed against grass and left a little blood. Only ever found 3 additional drops of blood in the dirt. I lost the trail with it hit a saltwater marsh. I figure the skin slid in relation to the shield and/or fat and closed the slit from the two blade hole. I'm amazed to this day and favor 3 blades for pigs for that reason. The shot was 17 yards, right behind the shoulder quartering away. Seems to have hit the off leg and didn't get a pass through.
This past year, I hit a pig a little far back with a Snuffer from my recurve and was able to keep on the trail of that gut shot pig. For pigs more of a hole that a slice gets my vote. JMHO. Steve