Very interested in your message - but I doubt I can help with your specific inquiry. Sorry.
I note that your family came from Germany, whereas mine can be traced back to the 16th century in the UK.
I was interested in the various spellings of the name, as they accord with some of those relating to my family. The name "Gooseman" seems to have been standard in my family since about 1650 but, before then, Parish Records variously refer to Gooseman, Goosman, Gousman and Guzman - the latter of which is similar to your "Gussman". In the UK, it all depended on how the local priest or curate translated into writing what he was told when he officiated at a baptism, marriage or funeral - and there is some evidence that some country clerics were only slightly less illiterate than their parishioners!
I have found evidence of "Guzmans" living in London in the 14th century but, as parish records were only kept from about 1540, there's no way of proving these were ancestors of my 16th century family.