As long as they are all IEC (the very common 3-prong hole on the back of each piece of rack gear that accepts AC from your wall) style inputs, you shouldn't worry about it. If any of the cables are significantly beefier/thicker (thicker gauge of wire) than the other ones, I'd use the fatties on whatever piece of gear draws the most current. For other possible uses of 'fatties' please ask Alphajerk for info

Check the owner's manuals of your gear for power consumption (Watts) or current draw specs (Amps) and use the thicker cables on the gear that has the higher numbers.
In 99.9% of cases, none of this will make any difference though. Don't sweat it.
I was surprised to see that you didn't list any Manley gear, Mike