I've got to go with Jones, too. Interesting how well they compare, height-wise, with Shkor at 6' 4 1/2" and Jones at 6'5". Shkor was a big guy for his time, yet 190 lb. Marciano seems to have taken care of him pretty easily (though not as easily as Walcott!).
Nelson was a very underwhelming performer, participating in 2 of the worst fights I have ever had the misfortune to watch.He has however metamorphasised into a capable boxing commentator.