3,500 pound Dexter axle bearing pre-load?

Some manufacturers call for preload, usually around 20 inch pounds, and some call for slight looseness (back off to install cotter pin). Of the thousands of bearings I have packed and or replaced over 38 years in the business I always preloaded to install the cotter pin. I never lost a bearing on a customers vehicle or on any of mine. As long as you can move the washer from side to side under the nut you will be fine. My car trailer bearings set up this way, Dexter axles, always ran at 100-105 degrees even in Texas during the summer. My utility trailer fully loaded never ran above 105. You do it how you want but my experience has proven that preload is the way to go.