Holonomic Drive WPILIBJ Support

[abigailthefox]

My team has decided to go with a holonomic drivetrain this year, specifically four omni wheels mounted in the corners of the base, at 45 degree angles.
I am the lead programmer for our team, but I have not previously worked on programming a drivetrain with omni wheels (I am also one of only two veterans on the programming sub team, and the other also does not have experience with this).
I saw on another thread (from several years ago) a note about using the mecanumDrive_Cartesian method in the WPILIBJ to control a holonomic drive similar to the one we are using. However, the poster only mentioned that the wheels were at 45 degree angles, and although the OP was talking about omni wheels and I have never heard of someone mounting mecum wheels at 45 degree angles to the base, I wondered if anyone had experience with/has used this method with a holonomic omni drive like I have described.
If it doesn't work, I would also be interested in some pointers on working out the math for this myself, and where to start.