FWIW, I had a cargo trailer that had much bigger magnets than the same 12 x 2 Dexter drum magnets that were on my fifth wheels and that cargo trailer stopped like a champ but the 5ers were terrible. The cargo trailer brakes had the biggest magnets that Dexter listed… I think they had white wires.
I wish I would have known the difference in the magnet sizes before I spent $1700 for disc brakes on my current fifth wheel.
I even tried premium riveted and pre-arced shoes on that lighter 5er with 10 gauge wire to both sides and there was minimal improvement from all of that work. The cargo trailer with the bigger magnets didn’t even need increased wire gauge to make it break so well. Craig