I have chosen an old power supply from HP 32V 2.2A for the steppers since the NEMA17 is not over 0.7 and the NEMA23 will be limited to 1A. I have chosen to mount it temporarely via some washers in the channel and brackets.
Washers - wide 18mm(5mm internal)x1mm ( I will use them all over the place so get at least 50)
Bolts - any head 20mmx4mm will do ( again take at least 20 )
Brackets - 40mmx40mm right angle for wood frame
Held in place by zip ties.
You can get a dedicated power supply and depending on your motors choose a higher rated Amps.
Rule is generally add your stepper driver limit +5%~10%. No point in wasting money on more power than that.
In my case I will limit the Amps via the stepper drivers to collectively 2A and it will not be even at 25% duty cycle (calculating from 8sec exposure and 2sec tilting cycle).