Why not make your own heightmaps with WM and set your own dimensions?
I don’t see the benefit in ripping off of others anyways, if you want to learn might as well go all the way and LEARN.
Edit: If you want to reproduce a real world location, NASA offers quality heightmaps online. I’ve never used them, they may or may not need some tweaking, but I’m sure they’re one of the better sources for that kind of thing. I mean, who could give you a better heightmap of a real world location than NASA?
WM to UE4 Tutorial - UE4 Wiki
A great tutorial on WM to UE4, along with heightmaps it shows you how to create a material for your terrain and offers more insight into what is actually happening - and why you may have previously experienced some issues along the way.
If you get a weird glitch and accidentally fix it, you didnt really learn anything. If you get a weird glitch and try to understand what happened, why, and how it can be prevented, you’ll most likely never experience that issue again, but if you do you’ll know what to do. Hope this can help any future lurkers who stumble across this thread, I know I did when I was having issues with WM to UE4, more specifically, the heighmaps I was exporting from WM were incorrect for UE4 - It was my fault completely. After following this tutorial, it worked perfectly. First. Try.