An important step in Static Architecture Conformance Checking (SACC) is the mapping of source code entities to entities in the intended architecture. This step is currently relying on manual work, which is one hindrance for more widespread adoption of SACC in industry. Semi-automatic clustering is a promising approach to improve this, and the HuGMe clustering algorithm is an example of such a technique for use in SACC. But HuGMe relies on an initial set of clustered source code elements and algorithm parameters. We investigate the automatic mapping performance of HuGMe in two experiments to gain insight into what influence the starting set has in a medium-sized open source system, JabRef, which contain a relatively large number of architectural violations. Our results show that the highest automatic mapping performance can be achieved with a low number of elements within the initial set. However, the variability of the performance is high. We find a benefit in favoring source code elements with a high fan-out in the initial set.