I do this by drawing a hand sketch diagram of the parts and the requirements and then you can see what you need.
Henry is right on about truck squat. To add to truck squat is bed weight. The question to answer for the truck is, with the truck bed loaded to go camping (lowers rear end), then what is it from ground up to the top of the 2" square hole?
Then for truck squat,
- The ball needs to be above the camper coupler on the T2499 when TT is level.
- Figure the tow ball needs to be approx 1" 1/4" to 2" higher for a 1/2 ton, 1" to 1 1/2 for 3/4 - 1 ton.
When you hitch up and set the WD on the truck, the back of the truck will be lower (squat) and the camper comes out level or slight nose down.
Like this, Trucked loaded, camper level, unhitched
The tow ball itself is in the middle of the mix. A hi rise tow ball like in the pic above the changes the relationship over a standard tow ball. Which do you have?
Hi rise on left, standard height on right
3 3/8" is the difference on a standard ball from the top of the hitch head ball mount up to the top of the 2" shank in the truck.
If you want, I can figure this out for you but need this.
If you post a few pics of the Reese hitch you I can tell what you have and what are the shanks you have now. If you have Reese PN's on the shanks tell me them.
Then load the truck with what ever gear you are going camping with (to lower the truck) and tell us ground up to top inside of the 2" sq hole inside the receiver.
We know the T2499 has a ball height of 18 to 18 1/2" when level.
If you want to do this yourself, see here some pics of others I have helped which may be of some help to you.
And this one, hi rise setup. This is a large camper with a 23" ball height, a 1 ton truck (GM), and the larger 2 1/2" shank. Same concept just compensate for the 2 1/2 shank
And this one on a Trailblazer
My 2004 T2499 on my 2003 K2500 Suburban
This link will take you to the Reese WD hitch catalog. A 4meg pdf download
Page D-18 has their shanks.
Notice the one you picked has no holes through the 2" shank section, your holes start below the 2" shank. That may or may not be an issue. Cannot tell yet from your numbers.
Hope this helps