The problem is that addresses tend to be unimportant in Christiansted. Even current residents don’t know the house numbers. Even Google Maps didn’t know. It finds the street, but not the number. I had tried every way I could think of, even posting a question to the St. Croix Message board at Ancestry.com
All this got resolved with my email. The St. Croix Landmarks Society just sent me a scan of a US Government Public Works map entitled “Old Limits of Christiansted Town” with each unit marked and numbered. The map is undated, but since it is a US Government map, it must have been after 1917.