Did my first hitch-up this weekend, and scaled it. Trailer is a Delta 294RK, so 33'11" and 9250# GVWR. Tows super easy with this truck. I got a 3500 CCSB w/air, and using a weighsafe middleweight WDH.
I started with regular air height, ball about 1" above coupler. I forgot to measure fender heights before hooking up, but it isn't that critical for this truck. Hooked up, no spring bars, front fender was 41". Applied spring bars, then set alt trailer height. Front fender was 40.75", rear fender 40.75". Trailer level, absolutely perfect.
When I scaled it, I really should have done a reweigh without the spring bars applied, but forgot! Didn't occur to me, I was just trying to hurry. So I only have fully loaded and hitched, and truck-only. Everything is way under the max rating, tons of margin, full tank of diesel. Yellow cells are from the CAT scale, green are the ratings. Rest are calculated.
The cool thing is, I don't actually *need* a WDH for this setup, I'm just using it because I have it and for extra comfort on trips. But just grabbing it from storage to take to my house to tinker with and back, I don't need to do the whole spring bar steps. Will be convenient.