You are essentially looking to accomplish one goal. That is to reduce the pressure caused by the added weight of water being held by the soil behind your wall. Anything else that you do that does not contribute to that goal is meaningless. If you do the post hole method, it will do very little because it won't drain the surrounding soil. The only thing it will do is provide a path for surface water to follow out through the weep holes. That can help divert a certain amount of surface water out of the area before it has a chance to be absorbed by the soil. The water has to be flowing on the surface and directed directly into those columns of stone for that to happen. The stone is not going to pull it out of the soil and the soil is not going to give it up until it can't take any more. Until you correctly understand water movement in soil you can't address the problem effectively. Try this to help understand the situation. Fill an aquarium half way with dry sand and then top it off with soil. Tamp it down a bit with your hand making a slight depression in the middle. Slowly drip water into that depression and see how long it takes the sand to get wet. You will find that the soil will be entirely saturated before it drains into the sand. It is no different behind your wall. The soil is still going to load with water. Replace what you can of that soil behind the wall with a material that will not load and you will reduce the pressure on the wall. Weep holes or no weep holes, that will be the biggest way you can affect reducing pressure on that wall. I really don't think you have much of a problem with surface water. Your roof drains are piped away, the house foundation appears to be just a few feet away, and the return walls make it appear that there is a steeper slope parallel to those walls than perpendicular to them. That makes me think that it is unlikely that you have completely saturated soil behind that wall very often, if at all. If that is the case, trying to make the weep holes work is a waste of time.

While ancient walls have been built like yours and still stand, Marcinde's method makes it easier to guarantee that you won't have problems. Your wall looks like it has decent batter, but it cannot be determined from the picture if it's consistent throughout. I think this is one of the most important components of dry-stack retaining wall stability. Keeping batter sufficient throughout will help wall longevity. With greater batter comes greater stability and, personally, I like the look of it as long as it's uniform. You could easily create a wooden triangle with a level attached to gauge the batter uniformly.

tabber, You may not be getting a response to your question because it is a little more complicated than a simple ratio that would require a certain footer for a given height. A demo program I downloaded from Retain Pro was helpful to me to assess the walls I'm building. I live in Arkansas and around here there have been a lot of DIY block walls built. Most of them have failed or are in the process of failing. Best I can tell, those that stood up over the years were built on a substantial footer and the block cavities have rebar and concrete. Steel stubs up from the footing to lock the wall to it in many of the block cavities. The good walls that are over 3 feet high were made with 12" block and they all have a system to prevent the ground behind the wall from becoming saturated with water. Not a cheap thing to construct. Lately, a lot of homeowners have built walls using the modular blocks that lock together. Close attention to the details will bring most DIY walls of this type to a good result. But they are what they are. If you like the look, it's not a bad way to go. If you want a true vertical wall that can have a finish of stone , tile, or some other material, then you have to look elsewhere. Timber walls are another possibility that some choose. But they aren't a permanent solution. The life span of a timber wall is also shortened if you have a long season where the ground is warm and you garden on the up side keeping the ground wet and fertilized. In the end I chose to do poured concrete walls. Most would say that this type wall is beyond a DIY project, but in my second year of wall building, I would say that there are no special skills needed, nor is the cost of tools that much more than needed for other types. One might call it an advanced DIY project, not for a beginner. I didn't have experience with concrete when I started but I did have a lot of DIY projects and was well experienced in working with wood. Most would do well to keep their wall heights to 3 feet and under. Keep in mind that down here the ground does not freeze more than a few inches deep, something that might be a major problem for those in colder areas. I now have about 200 feet of wall up with another 125 to go. One of the things I like about poured concrete is that I don't have a lot of really heavy lifting to do. There is a lot of labor, but the form panels and other materials are not much more than 20 pounds, something an older man can handle. James

Assuming the landscape block manufacturers know how to make CMU that is less susceptible to giving up its salts to water passing through, the best way to reduce efflorescence is to provide good drainage behind, down, and through the wall.