Got my setup working now, and damn it heats up quick. Also reaching 100 C is a first … will make printing ABS a whole lot simpler.
Regarding powering the main board through a HCJ-IPM-V2; well, it only partially worked. Heating the extruder to 220 C and moving around X and Y axis at the same time worked fine with a current of approximately 2,6 A, making the unit get quite hot (but not scorching hot). As soon as Z axis movement was added though, and the stepper started grinding, the regulator failed and the printer brown out:ed. It might be possible to add a beefy capacitor after the unit to compensate for the Z steppers gluttonous needs, but for now I just keep the original supply in tandem with the 24 V one for the heat bed.