OMG - thank you for clearing up the north/positive confusion. I had no clue, I'm glad I kept asking. I would have been putting them on wrong. I am totally magnet illiterate. I assumed one side attracted & one side repelled.
To create a magnetic field, do you put magnets N to N or N to S? I assumed N to N - so these other magnets probably wouldn't even work? They are to pick up 100# of material & have a metal loop on them to attach a rope.