Working with a beastly hardware kit.

[truly_bent]

For starters, those LH2322-P300 stepper motors are size 23 and rated for 3A per phase while the Rambo 1.2a board is only rated for 2A. If you did try to drive these motors with that board, i'd expect fuses to pop at least. If those driver outputs were not protected (i assume they must be) you'd be letting some smoke outta the wires.

You can break the drive signals out and use stronger drivers for those motors.