ostie01,
Your driver board max power supply rating is 32VDC@7A, with a recomended supply of 24VDC@7A.
Now if you were to use two power supplies wired in parallel you could get 24VDC@12A which is over the driver board rating.
This is not good.
Should the filtering quality of the power supplies be inferior, a properly rated capacitor may be desired. My preference would be to provide the additional filtering and some surge capacity via the capacitor if they were parallel connected ( but that's only my opinion).
I only glanced thru the 20 pages of the power supply manual and noticed there is info on series and parallel wiring.
Pay attention to it.
With no motor curve info, which relates wiring confirguration to speed, torque @ some voltage, you can not forecast motor preformance ( it will be trial and error in finding it via tuning). The driver board info shows max individual drive fusing to be 2.5A. This says any individaul stepper current draw will be limited to 2.5A MAX which futher defines how you would wire the steppers.
Also as a total ( three steppers with a total current draw should not exceed the 7A rating of the board ).
RICH