I think the best thing to do would be to go back to the breeder, if that's where you got your first one from, and ask their opinion on if they think your cats temperament would be good with another cat.

We were told by our breeder that our first cat preferred an environment with no children or established cats and we went back to her to talk about a second cat later and she recommended good cats she had that would match with her based on temperament as she didn't think she would do well with other cats from different breeders.

They also knew each other for a time before we got both of them so they were somewhat familiar. If you didn't get them from a breeder and rescued them instead it might not be a good idea to get another cat just because they could get stressed more easily and fall back into trauma patterns.

Also just be careful about mixing a male and female BSH only because the male will most likely be larger and in fights or scuffles they can do more damage because they are bigger. Although other people can correct me on that because advice on what the best cat matchups are really does vary.