hey ryan, I got my cable at princess auto, i can't remember what mine is 3/8 or 1/2",.. but I think i got 3/8, i believe it's rated for over 25k lbs of pull, so no worries there.
They also have everything to make an eye as-well
I was only able to fit about 75' on my winch, but I put on a snatch block so I only have about 37' of pull,.. but I had the extra 25' and made a steel line with eye's
I remember watching a mythbusters episode on cable,.. even with 1/2" cable at over 30k lbs of pressure, it didn't cut a pig,.. just bad rope burn.
Even if we pull at 15k lbs, the cable will for the most part go down (wear high ankle boots
)