The customer did not specify a wall height, but did mention that he's considering using a stacked block construction with no mortar or other internal support or strengthening material being used.
The following is the Olde World Stone & Tile Molds actual email response to the customer:
You didn't mention how high the wall is going to be, so I will give you my general feelings on retaining walls. If the wall is going to be over let's say, two feet, I would always opt for using either concrete blocks or poured concrete for a retaining wall. If you compare your costs, you will probably find that you come out ahead with those two methods versus larger pre-made blocks... especially for higher walls. The other concern I always have about just laying stone blocks on top of each other is the strength of the wall. How strong the wall needs to be will usually depend on what the wall is supporting or holding back (retaining), your climate, soil type, heavy rain activity, and other factors. Again, if your planned wall is to be around two-feet high, these concerns are probably not as much of a concern. I just thought that I would bring them to your attention.
Our stone veneer, especially our Ledgestone veneer was designed just for the purpose you mention... to cover concrete block and poured concrete walls. If you are going to do the work yourself, concrete block would be my first choice as it's much easier for one person to do. You can then make your Ledgestone veneer, and pretty much just "lick and stick", as they say in the trades. You need no lathing or other extensive preparation. Just apply a scratch-coat, and then start applying the stone. We can even help with instructions and other installation tips.
Below is a photo of a large wall being covered in Ledgestone veneer. Note the sides of the steps have not been completely stoned yet. There are other photos below of the stone as well.
In the second photo below, in which the Ledgestone was also made and installed by a customer of ours, (Mr. Mazzoni), you will see that the garage needed to be covered with a sealing paper/tar paper and have lathe applied, then a scratch coat applied before installing the stone because it was being installed over wood. He cheated a bit, and combined and applied the scratch-coat and installation mortar coat at the same time. The scratch-coat should normally be applied by itself... then install the stone.
As far as Stackstone/Ledgestone versus the Castle Stone style of stone... if you are torn between the two styles as far as the "look" that you want... Castle Stone will take a lot less time to both make and install. Depending on the size of your wall, you can mix in some (up to) 18x18 Castle Stones to speed the job along. Each one of those covers 2.25 square feet, and blend in great with all of the other Castle Stone sizes to give a true castle look.
You can also blend in some Castle Stone or Limestone with your Ledgestone installation to speed that along a bit, should you stick with that style. That's what the customer who did the wall on our website used, along with some larger natural stones.
If I can be of further help in any way, please let me know. We are always as close as your email should you need guidance or support with your project. And complete FREE Step-By-Step Instructions are always included with each mold purchase.