Congrats on the new rig!!!
How was the trip home???
Measuring the front fender height when adjusting the wd hitch once the trailer IS LOADED can get you very close, but if you have a CAT Scale nearby, weighing the truck & trailer will confirm how well the wd hitch is set up.
Weigh 3 times to get all the needed weights.
1: Truck and trailer ready to roll down the road- wd bars latched up.
2: Truck and trailer, but woth wd bars unlatched, in the bed of the truck.
3: Truck only, leave hitch in and wd bars in the bed.
If your front axle weight in #1 is close to or the same (without being higher) as the front axle weight in #3, then you are set up pretty good.
Add the trucks front and rear axle weights in #2, then subtract the total of #3. This will give you your loaded tw (tongue weight).
Didn't the '09 Gm trucks have the 6spd with the 5.3? Or was it certain models only? What rear gearing do you have, 3.73 if the 4spd trans?