I graduated from CST, and would fully recommend them.
To actually work on guns you have to be in the last section of the school. That is the design and function section. The teacher Stewart is a very knowledgable pistol smith, and will check all work done by students. By that time in the training all the bad students have been weeded out. It would be cheaper to bring your gun there, and they will not let it be turned back in unless what you wanted done is done, and is satisfactory. They will also fully dissasemble, clean, oil, assemble, check headspace, and testfire your weapon to make sure it is working properly.