hi JR! "Again, for dressing purposes, I am not looking for the most flattering shot, but the most accurate one." Aida and Janet both did an excellent job of addressing the technical aspects of this concern. I wanted to say don't forget about the human element. Everyone has different preferences, there is no 'neutral viewpoint' as to what looks best on someone. According to who? Dressing is a craft and sometimes an art, so subjectivity will always be present.
That said, if you photograph different outfits and garments with the same camera setup and in the same pose, you should be able to compare the ways that the different outfits and garments affect your proportions. Do you think this might help you decide which you think flatter you most?
Physically i'm low-contrast and pretty curvy, so i tend to look pretty awful in candid photos. So when i stated a style blog i set about learning how to photograph myself in an appealing way. The only thing i would emphasize here that hasn't been already is that learning how to pose makes a big difference! Makeup and hair can help, too. Practice, study pictures of yourself and others that you like, and don't be afraid to change things up and see what happens.
And just like the camera loves certain people, it also loves certain types of clothing. Floaty, drapey, loose garments that look feminine, flattering and charming in real life can be hell to photograph in a way that translates their appeal. For those types of outfits i say trust your mirror and a good friend (unless you have mad photo skillz!)
Frankly, i like the way i look on videotape best. Believe it or not! Growing up i always looked crummy in photos. In my twenties surveillance cameras came into use and wow! i looked great in the 7-11! Nowadays even many cellphones come with video - if you're very curvy (not big, you just don't have a lot of straight lines - you have curly hair, googly eyes, and so on) i suggest you try taking some video of yourself in different outfits and see what you think. For some of us it's a real eye opener! steph