Most of the loading info you will get as you go. If your pulling a 53' trailer the general rule of thumb is lighter in the front. Heavier toward the rear. This allows you to adjust or slide the weight around on the tandems. The tandems generally slide about 500 lbs per hole when adjusting the wheel base. It does not affect anything in front of the fifth wheel mount pivot point. Say a 22 pallet 45,000 lb load at IWX I load single Double turned single double turned the rest double straight in all the way back. The tandem would be right at the 40' hole. 79,350 gross 34,350 tare I would be 34,000 on the trailer 33,350 on the drives 12,000 on the steers. It will come don't sweat the small stuff, pay attention. And don't forget to scale out on load over 32,000.