I can see how that Hyper 7 running the 1P setup with the 9XL might seem like it's doing ok. A 9XL running 12/46 in a buggy is kind of undergeared and probably isn't demanding much from the batteries. If you bumped that gearing up to around 16/46 (which is where I would run it), then I think the batts will start to sweat a bit in a 1P configuration. As I said, I ran the 5S1P setup in my 8ight T with the 9XL geared 16/46 and the batts got up to around 130* in about 5 minutes, which was how much runtime I got. Well, a bit more, but the batts heated up pretty quick.

I suppose it's all a matter of how you want to run. Knowing jhautz (having seen videos of his stuff and how he runs), I think I can safely say that the 1P config isn't going to work very well for him.