I personally like Bilsteins, but they will not help soften the ride for tires with that much pressure. Assuming the tires are rated for that pressure, which they probably are, that is where they should be towing the fifth wheel in your signature. However that is way too much for driving empty. Besides the rough ride, the tires will wear prematurely (wear the center of the tread) and you will have decreased traction due to a smaller contact patch and the tires tendency to bounce over bumps and at times be airborne and not in contact with the road.
Individuals who use their vehicle primarily for towing and only short trips empty will often remain aired up, but if most of your driving is empty, you should air down and then air up when towing. There should be a sticker on the driver's door or B-pillar which will have the tire pressures for empty and maximum load.
My fifth wheel is much lighter than yours and I run 46 PSI front, 42 PSI rear when empty and 50 PSI front, 62 PSI rear when towing. The Cummins is much heavier than the Hemi, so the front of your truck is going to be heavier than mine, but I would think empty you should be about 50 to 55 PSI and rear 45 to 50 PSI.