My first tarantula was a female rose hair and a complete sweet heart. She is still my favorite. I also had a female rose hair rcf and a normal rose hair that was a male. Both of them thought they were obt's - lol. I wouldn't worry too much about the smaller one unless her butt starts to shrink and her but looks good (that sounded kind of creepy). I have a G. pulchra that is about the size of a half dollar that has not eatin in a looooong time. The butt still looks good on him/her so no big deal. I am excited for it to molt though because I think it is a female and I am dying to know. Anyways, beautiful T's