In my own calculations, when I upgraded my Wanhao D5S Mini, I simply ensured I have a good overhead for the Stepper drivers and it simply works.
On my setup I am running the DuetWifi, 4x Nema17 stepper motors (at just over 1A per phase), 5" PanelDue, 200x300 heatbed (estimated wattage of 160W @ 24V), 30W E3Dv6 a bunch of fans (including blowers etc) a RaspberryPi Zero W with a camera and an LED strip (as well as obviously the small current items). All of this is powered through a single Meanwell LRS-350-24 power supply - and based on my power monitor, the unit is not close to being overloaded, even with all heaters on and the motors and fans running at full speed (last time I checked, it was near 250W).