22 magnum behind the ear towards the opposite eye, then immediately penetrate the left arm pit or in a hogs case "leg pit" to the heart with a knife, that gets them bled out real good, I know of some that go in just in front of the front shoulder but that way is a lot more difficult to hit the heart.
Of course if they are little boars then cut them and feed them for a while and let that boar flavor get out first, and whatever the gender make sure you don't get them all riled up before you do it, that gets all the adrenaline and what not flowing and may show up in the taste of the meat. Try to make sure they have been very calm for a while before you do it.
However you mentioned presentation, are you mounting a 30 pound hog? If so then skip the 22 mag and go for the second phase mentioned, be prepared for some hellatious squealing though if you skip the 22 mag. the only problem with that way is you can't maintain the part about keeping them calm first if you are chasing them around a pin. Hope that's not too graphic.
