Questions about mecanum wheels

[Todd]

the WPILib Joystick class has a GetDirectionDegrees and GetDirectionRadians, I'm sure Labview has something similar

Actually it unfortunately doesn't (At least as far as we can tell). We also had to do the conversion from X/Y axis to direction/magnitude.

When we push the main joystick full forward, and give the holonomicdrive.vi the equivalent of 1 magnitude, 0 heading, and 0 rotation, the motors all go in the same direction but at about ~70% power.

This is also true and is how the holonomic vi is coded.

If you want to change it so that your motors are running at full power I'd advise making a copy of the holonomic vi and reworking the math inside of it to your liking.