19.5 tires are overkill on a DRW truck. With my SRW truck I replace the factory tires rated at 3095 lbs with Nitto tires rated at 3750 lbs and so had support for up to 7500 lbs or 4000 lbs of payload with the truck. with the addition of Supersprings my Chevy 2500 was dead level with 4,000 lbs in the bed.
Only if I was going with a camper that had a dry weight of more than 4,000 lbs would I have to decide between DRW or going to 19.5 tires and rims. The 19.5 rims and tires would have cost me more than $3,000 and so not a decision to make for grins.