I'd go for the max current draw that you can afford and fit (weight and size wise). That way, the voltage drops less under load, you get more runtime, and you don't have to worry as much about how close you are getting to the C rating of the cells.
Well, I am planning to use 6s lipo. Although I could try 5s lipo.I was planning to use the Maxamps 3s 8000 but they weigth around 19 ounces each, which is not to much difference from the 8 cells packs that I am using now, that wheight 22 ounces each. I know it would be more voltage but i want the lees weight possible.:037: