I'll second the Slick Tricks, the Magnus Stinger is a good head as well but if already having flight problems that head will likely magnify it.

If you have flight problems at 30 yards you need to tune your bow to the broadheads. You should be able to get most any head to fly true to your field tips with some tweaking.

I would not recommend shooting a hog in the neck with a bow. Some may disagree and that is fine. With a mechanical head your penetration is going to decrease, couple that with an arrow that is not flying true and hitting square and you will end up with a lot of hogs running around with arrows sticking out of their necks.