So I drove with the camper 40 miles today.
Driving motion added about 1" to the squat, so now the main springs are firmly engaging overloads. Still about 1.5" to rubber axle bumpers.
I also weight the truck and I have 9250 lb on 9900 lb rated rear axle.
I drove 70 mph on the freeway and it was 1-hand driving, so can't complain beside sensitivity to side wind.
Driving via the scales show that my camper has center of gravity behind the axle as it took off +- 100lb from front axle.
Another observation - my 4300lb winterized camper "grew" to 5600lb with just regural stuff and full water tank.
I had rear holding tanks empty, while full water tank is right behind the cabin, so there is not much I can do to move center of gravity.
Generator is in the rear, propane tanks and batteries as well.
I can move 15lb tool box from the rear into truck cabin and that is about it.
Bottom line, I am already pretty happy and will be happier gaining the 1" back, so I placed order on sack of hockey pucks.