Power Supply for Gecko 320 and servo motors for 3 axis router

Hi folks -
I'm putting together the power supply for a 3 axis router using 3
Gecko 320 drives with 3 DC Brush servo motors at 360 oz-in peak
torque. The motors are rated at 36 vdc. I want to make sure I'm
sizing everything correctly. My guesstimation is total maintained
current draw for all 3 motors will be around 12 amps (20-25 peak amps
per motor). So the math works out:

80,000x12amps/36 VDC = 33,333 microfarads for the filter cap.

Queries:

Is it OK to use a filter capacitor between 33,333 microfarads and
100,000 microfarads? (I think rule of thumb is 1 to 3 times required).

Is a 50 volt capacitor adequate for the 36 Volts out of the
transformer? (I think 50 volts is a standard capacitor rating, the
next lower one being 35 volts)

Though I understand what a capacitor is and does, what's the function
of these filter capacitors (e.g. what would happen if I didn't use
them?)

What rating or capacity besides the 100 or so volts do I need in
order to ensure the bridge rectifier is sized asequately (I really
don't want this to be the weak link in the circuit, as bridges are so
cheap).

Is a 100 volt bridge rectifier OK for the 72 volts total between plus
and minus 36 coming out of the transformer?

What's the functional difference between a toroidal transformer and
a....well, square? one? Is one better suited than the other for this
application?

Any great clues on finding good prices for quality components like
bridges, capacitors and transformers would also be used and
appreciated.

Powerless,
Scott