Auctions are an important class of mechanisms for resolving multi-agent allocation problems. A genetic algorithm (GA) can be used to design auction mechanisms in order to automatically generate a desired market mechanism in an agent based E-market. One study found a new hybrid market mechanism never before found in the real-world which has very desirable market dynamics according to a measure based on Smith's coefficient of convergence. However, the auction space used in that study did not contain realistic single sided auctions. In this paper, a more realistic auction space is proposed and explored by a simple GA. The hybrid market mechanism can still be found which shows the hybrid market mechanism is not an artifact of an unfaithful auction space used in previous experiments.