Yes, I too was intrigued by the Handsworth reference, a long forgotten oasis buried in the urban jungle of Birmingham.
It is no surprise to me that Alison would set up office in Detroit and specifically in the Penobscot Building. I don't think the building was finished at this time, but it when completed I think it was among the tallest in the world - maybe the tallest outside of the two skyscrapper giants, NYC and Chicago, but I don't know for sure. In any case, Detroit was a hotbed for architecture (buildings) riding on the back of car companies and new systems for building steel framed factories which A Khan helped to develop. There are a load of terrific buildings in Detroit!
Also, Detroit was centrally located for many of the courses Alison had already completed and with the car industry boom there was no reason to think Detroit wasn't going to continue growing and building courses. Michigan Central Station had not long been open and the rail tunnel under the Detroit river to Canada was in full blast. Detroit was a city on the go. Unfortunately, the MCS was ging to slowly slide into the decay we see today once the depression hit and the use of cars became king in Detroit and the US in general. The building's fate is still in the balance - hopefully it can be saved or its another chunk of the city (in this case Corktown) which has little hope of being revitalized.
Ciao