I just had a look at my older SA 3sp hub and the bearing housing on the left side appears around the same size as the
common CG wheel center. I assume you are using a rag joint set up? Cant speak to the newer SAs as I no longer have any to look at. I run the Nexus from the right side. Its bearing housing would require a larger hole on the left.
Hope the helps, not really sure what you are building.