This is the weighing process i was given at many FMCA Rallyswhile full timing 10 years. Be sure to keep your engine running to maimtain ride height.
I had the Tag pressure so i had 15K on our 07 Executive, with 315's al the way around. As you burn fuel you reduse the steer axle weight.
Weigh the coach. Four , or Six corner weight is the best, but single axle weights will be OK too. Fuel and water full. Black and grey tanks empty with your stuff on board. CAT scales at many truck stops. Tell the clerk you want to weigh a coach. There is an intercom at the scale so you can communicate with the clerk. There will be 3 platforms for3 axles. Steer axle on the first, Drive on the second, and if applicable, Tag on the third. Keep the ENGINE Running, so you stay at Ride Height.Get the print out from the clerk. IF you have a tag axle, you may have to adjust your DOWN pressure to move weight as needed, and after adjusting your down pressure on the tag, REWEIGH the coach. Now go to YOUR tire Mfg. inflation charts for the correct COLD inflation.