Here's my directions for installing DWO's. First, this really mostly applies to a 2836-2. When I use a 2824-2 I usually swap out the date wheel to one from a 2834 or 2836 since it raises the overlay to where it won't rub on the movement gears. The 2824-2 DW sits lower in the movement and you may have to actually raise the DWO slightly off the DW. That's a whole different set of problems.
Anyhow, I found a quick and simple way to align it. I first make sure the date wheel is in the proper position on the movement. You can see the spring that holds the date wheel in place roughly on the opposite side from the stem and make sure that is in the center of the two click feet that hold the DW in place. Then you know the DW is where it should be when the watch changes the date. That's important otherwise all the dates will set too high or too low.
Then put the dial onto the movement and make a small mark on the right hand edge of the date wheel, centered in date window. take off the dial and extend the mark all the way to the edge of the DW. This way you'll be able to see it after the overlay is put on. Take a good look and make sure that it's very well centered. Then, remove the dial and use that mark to center the date number. Let's say we use the number 1 and make we sure it's absolutely centered on the previous mark we made. Then center the whole overlay on the the date wheel making sure the number one stays centered on the mark. You can eyeball that and it's easy to see when all sides of the DW sticking out from the overlay are equal.
When you have the overlay perfectly centered on the DW and the number 1 still centered on the mark, you can drop the dial back on and run through the numbers and make minor adjustments as needed. Usually, if you followed directions and centered the overlay on the date wheel, all the numbers will line up perfectly.
Also take a good look at the back of the dial and make sure it's clean and nothing is sticking out. And you should be good to go.
After you've done it once, it probably takes longer to write this than it does to install an overlay