Q1 - Wire Guage Computation for the Orange Power wires - Each Side: 18 Amps, 90 Watts 16 ft (one way);  Total: 36 Amps, 180 Watts 32 ft (one way).

    Q1a - Do I compute wire size based on each side: 18 Amps, 90 Watts 16 ft (one way)

    Q1b - Do I compute wire size based on each side: 36 Amps, 180 Watts 16 ft (one way)

Q2 - Wire Gage Requirement - According to this web site: https://www.ledspot.com/ls-power-cable-calculator

    Q1a requires 14ga at 1.0 drop multiplier or 12ga at 1.5 multiplier
    Q1b requires  8ga at 1.0 drop multiplier and 8ga at 1.5 multiplier

Q3 Assuming I have not made a glaring mistake above it appears that it would be cheaper and easier for me to use two DC5V 20A 100W LED supplies instead of one DC5V 40A 200W LED as in the second diagram attached https://www.dropbox.com/s/gknkaoeaky0n0tx/Circuit_B_04.jpg?dl=0 .  Now i would not need anything larger than 16ga wiring????

    Q3a Does the above make sense?

    Q3b Given that I actually have four "sides" (rather than the two shown) I will need 4 power supplies (NOTE: I plan to be able to turn each pair of "sides" on and off by each of two wall switches which will control power to the supplies).  Is the brand/type of supply I am using overkill for this application? https://www.amazon.com/gp/product/B01LZF6NK6/ref=oh_aui_detailpage_o00_s00?ie=UTF8&th=1

Q4 I have assumed that within reason the length of the control circuit is not an issue - correct?

Q5 I would prefer to control all of this from one Arduino so I have shown the control wiring as a daisy chain including each "side" and the small 12 LED strip shown at the bottom of the diagrams.  I also would daisy chain in the second pair of sides mentioned just above.  Given that the strips I am using ( https://www.amazon.com/gp/product/B01N0MA729/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 )have a dual pair of leads for the VCC and GND and that I am using different 6 power supplies total how do I wire this (I assume i can get polarity correct to prevent shorts).  Or am i simpling forgetting my EE training and i do not have to worry about parallel connections between DC connections?

Q6 I just realized i may have a problem if I turn off power to one Power supply will that set of leds try to power off of the control line?

Q7 Am I making this too complicated - do I really need a separate Arduino for each power supply?????