Power cord - 5 ft vs 10 ft ?

Long enough to reach from your equipment to the wall outlet or power strip.

depends on how far is your outlet location

A high end cable manufacturer/retailer whose name everyone here would recognize and respect (and name I will not divulge) told me to buy the size I need. He said retailers push the buy at least 2 meter for best sound BS solely for extra profit.  And he listens extensively to his products and does not hear a difference between PC cable lengths.

@hilde45

Reviewed your system pictures and award you the prize of most thoughtful presentation of pictures I’ve ever seen.

Interesting system and took interest in all those dedicated circuits you have.

Thickness of a power cable certainly is important as you indicate do to better noise control via assumed better shielding.