I need advise before getting another cat....?

I have a male Siamese cat. He is 3 years old. I want another Siamese but I am confused as to what to get. Should I get a kitten? Or a cat his age at the shelter? Male or Female? I have tried bringing a Tabby home when he was 5 weeks old and he terrorized her. But they had babies and he was a great daddy cat. Since he is older I am thinking he may not freak out so bad but he is a spoilt ***. Any suggestions or advise?