Initial WD set-up

Call the seller and have him level the trailer and measure the height from the ground to the center of the coupler. Set your ball height about a inch lower than that.
That will give you a good starting point to get you home so that you can tweak and dial it in later.

Expect the actual tongue weight (fully loaded for camping) to be more like +/_ 800 lbs based on the brochure info. The WDH will add another roughly 100 lbs. You'll have around 900 lbs of payload that should be deducted from the payload capacity sticker on your door pillar sticker to ensure you aren't overloaded.

The ball on the truck is usually initially set at 1" higher than the TT's coupler (with level trailer) to allow for settling/squat in the rear of the TV.

You'll want to measure the before and after front fend height to get the proper amount of weight transferred back onto the steer axle. You want to end up with the spring bars approx. level when the proper amount of weight is transferred up front.

Won't take long to do an initial setup to get close to what it needs to be. Doesn't have to be exact and you can tweak it at afterwards when home and have the trailer loaded up. You really need to have adequate weight transferred back onto the steer axle for safety. +/- 900 lbs is a lot for a 1/2 ton.

X2 on an inch higher

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?