I'm stuck: Trying to set up Diagonal Rod Arms

Okay.

Still not sure about the carbon fiber arm lengths. the so called Delta_Dagonal_Rod. (These are mag arms if it makes a difference).

My primter is based on the Cerberus Pup which is 500mm tall ans 170mm build circle. Mine is 650mm tall, and a 220mm build circle. I've measured the important configs below. Can anyone help me calculate this last dimension?

#define DELTA_SMOOTH_ROD_OFFSET 160 // mm

#define DELTA_EFFECTOR_OFFSET 30 // mm

#define DELTA_CARRIAGE_OFFSET 27 // mm

#define DELTA_DIAGONAL_ROD ?????

Thanks