From experience bi/pan women like good asses and a strong upper body or tits in the case of women. Its probably because they are attracted to those features on a sexual level and those are features that are possible on both men and women. On the other there are comments that said that their bi girlfriends were also attracted to much more masculine features as well so i guess this theory doesnt hold up that well. Also just in general i think a good ass is the best feature to put your points into, many straight and bi women and many gay men like em.