If you want to shoot instinctive, go with split. It takes the arrow more out of your line of sight. If you want to gap shoot, go three under. It'll make your gaps much smaller and easier to set. As for three under not being allowed in the traditional class at many3D tournaments, I've never found it to be an issue in over 10 years of shooting 3D at the local and regional levels. Now, it is taboo in the longbow class with some organizations, but I've even seen that rule become more relaxed over the last few yearsat different clubs.

Grip choice is really a personal preferance. I personally like a high wrist grip, but that's me. The best scenariowould be to handle and shoot several differentbows with varying grips, but that isn't always possible. Sounds like this is your first bow. Go with the medium grip. It's a nice compromise between the two. As you shoot more andget the chance to try different bows, you may eventually swing one way or the other on the high wrist/low wrist issue.