Almost a minute doesn't seem like a long amount of time, as long as you're doing something that's visible and engaging to the audience. (I say this because I witnessed a dancer once enter with her back to the audience... doing undulations. No one could see what she was doing except the dancers outside the entrance she used!)

How long is it relative to the entire piece?
One minute doesn't sound like a long time, but it can feel much longer when you're watching it.

IMO "almost a minute" is too long to stand with your back to the audience. IMO the fronts of us are generally more interesting than the backs of us. Additionally, while some movements like taxim or shimmy can be interesting from the back, many movements (chest circles/lifts, hip lifts, etc.) are quite obscure from the back.

Often it helps to videotape one's performance to get a different, more objective point of view. I suspect you will discover that certain important subtleties are missing. However, if you videotape your performance and still really like how your choreography looks, then go for it. It's YOUR dance.

I think it depends a LOT on the style and concept of the performance. You might see the backs of a group of modern dancers for several minutes, but they're usually creating interesting shapes with their bodies and using the space in unusual ways.

Most bellydance is less dynamic than that, with smaller movements that are more about watching a person on stage than a group of shapes on stage, so unless you're going in a unique, extremely dynamic direction with the piece, a minute is pretty long. 30 seconds or so is probably the max amount of rear-time I'd do in a bellydance piece.