The arrow needs to spin to stabilize the broadhead. so, you use helical or offset to make it spin once it leaves the bow. So, no matter what way you set-it up on the rest the blade will fly the way it's going to fly based on tuning or the wind.

The X VS + goes right along with the matching the 3 blades with the vanes. This guy told that guy who told someone else and before long everyone believed it.