Complex sentence: An analysis of his work will show, however, that although he has a number of small houses to his credit the largest percentage of his work was done for what would be considered upper middle-class clients.
Split into simpler sentences: An analysis of his work will show, however, that he served a broad-based clientele. He has a number of small houses to his credit, but the largest percentage of his work was done for what would be considered upper middle-class clients.