@Cyborg Pirate, I see you already bought, so this is probably too late for you, but I'll throw this out there anyway.
I have both (HS and D for doubles). I prefer donut, for ability to vent while in any kind of head down position.
But, to ME, the actual shape is more important than whether it's a HS or D. I have both types that give me good trim easily and without need for a tail weight. I have also had both types (but different models and brands) where the wing shape was not good (for me) and the only way I could get good trim was by using a tail weight. I.e. lift distribution was too much towards my hips/the bottom of the tanks.
I have both (HS and D for doubles). I prefer donut, for ability to vent while in any kind of head down position.
But, to ME, the actual shape is more important than whether it's a HS or D. I have both types that give me good trim easily and without need for a tail weight. I have also had both types (but different models and brands) where the wing shape was not good (for me) and the only way I could get good trim was by using a tail weight. I.e. lift distribution was too much towards my hips/the bottom of the tanks.