Not sure if it's what the OP is getting at, but what I'm curious about is:
What conditions lead to Mako and Torian's romance arc? Does it happen regardless of the BH's gender? Is it based, as I've seen described, on Mako's and Torian's relative affection levels? And does it have any impact on your character's ability to romance one or the other of them? (This last, I think, is what OP is concerned about.)
Playing a fem BH, I'm planning to romance Torian, but Mako's affection will certainly be higher than his when I first get him as a companion. Should I be concerned? Should I sit Mako down for a talk, gift-spam Torian, let them have their chance, or what? (Wait, do I really want to be a rebound?