Context is everything, so for your project I would think about who were the participants (social class, motivation), where they were (nightclub? carnival? seaside? ring event?), and the intended audience, because that should tell you a bit about what the boxers would be wearing. It could be anything from dresses to swimsuits, but the links below should give you some ideas. I would also look at some of the historical photo collections sites, such as the Library of Congress American Memory Collection and the British Pathe Film collection which I know has female savate from that era and probably boxing as well.

Female Single Combat Club site

British film still on female London boxers.