Oh, you mean the "Hollow Tree"!? Yes, I own it and thanks for the compliment.
I've been wanting to try it for years, but it wasn't until I had the proper mixing equipment for bubble free molding and casting. I have a peeve about bubbles and due to the fact that almost every modeler today owns a digital camera, I just can't see having a scene ruined by some smooth, scale bowling ball size hole in the stone wall in the background.
Cut stones have splitting/fracturing drill holes along with lifting holes. The top-sides have also been worked to represent a chisled and dressed look. Nobody modeled them, so I did.
Also, alot, but not all stone walls have a slight lean (1-5 degrees)to them, which is easy enough to model using the other manufacturer's walls, until ya get to a corner. It creates a compound angle which is not easy to cut out of a sheet. I figured it would be best to address the corners first, then build to it.
I did alot of research by looking at actual abutment stones up close and found out that simply casting and breaking off stones did not cut it for me (pun intended)

. I don't care for carved stonework, it just doesn't look right to me, so I use the fracturing method. However, that's where I diverge from the other manufacturer's techniques. I end up working the stones over quite a bit. Loupes don't cut it, so I have to resort to staring into a double barrelled microscope. It IS tedious work, but well worth the effort. I also like to do high density pen & ink drawings, so it fits right in.
Plus, I didn't like the idea of having to cut up large walls. Instead, I decided on the "build-up" concept, which is a lot more flexible.
I'm not planning on leaving my day job to do this, but it is thought provoking, model railroading and fun.:thumb: