I got a new gun the other day. I bought it for it's own sake, but soon realized that it is very good for helping me with my XD skills.
It's a HW 40 PCA - a single stroke pneumatic .177 air pistol. Here is is next to my XD40SC.
The grip and grip angle are pretty close to the XD's - the XD is a bit longer front to back, but not by much. Here the XD is sitting on top of the HW:
The HW comes with truglo sights, so if you shoot with fiber optics or tritium sights you'll feel right at home.
So, here's what I do. I have a pellet range set up indoors. I load the XD with snap caps, as I would for a dry fire session. I load and fire the HW first. Each time I have a great shot, I then pick up the XD and do a dry fire. It is actually surprising to me how the back-to-back experience really tells me when I'm doing something wrong with the XD.
I don't know if this will turn out to be a sound training regimen or not, but since I'm going to be shooting the HW anyway, why not add the XD into the mix? I bought the HW for general in-home accuracy practice (more for .22lr bullseye pistol than tactical shooting), not to mimic the XD in any way. I think it will pay off.
Regardless, being able to run 100 shots a day through a gun can't be a bad thing. I only get to the range once a week at best. The HW has .20" CTC accuracy - enough to shoot a 10 every time if I do my part.