I tend to think that the braking figures were probably fairly accurate. I am tired of banging on about this, but the construction of the steel brake plate lends itself to progressive and sometimes lethal degeneration. (A bit like Yours Truly, responded the Chorus!) You MUST ensure that the shoe pivot pins are parallel, and remain so. You must also strengthen the cam boss and the brake anchor pin. I bet my dog's dinner that any 60 year old well-used plate will have pivot pins that look like a psychotic's divining rod. It is not hard to re-engineer the plot without going to the expense of alloy or 8" plates and brakes. Gentlemen, I await your encomiums or howls of censure.