Most of my cords are #12. I have a couple #14 cords that I got for free and I use them only for lights or my dog clippers. Anything else goes on a #12. I probably have 500' total of #12 cords from my days as a plumbing contractor.
I roll them up in a figure 8 on my arm, then match the loose end to the captive end and wrap the loop around the bundle. The last thing is slipping the end of the loop over the bundle. Nice compact package that will never tangle.
To hang them I typically use a 3/4" pipe flange and a 3/4"x18" pipe ******, mounted on a 2/4 somewhere in my shop. Just slip the cord over the pipe.
When transporting I just throw them in a box, crate, or bucket. Wrapped the way I do they are compact and never tangle.