As you have learned, a fast lens is the tool of choice to isolate your subject and minimize the ISO setting to keep the images as clean as possible. When shooting sports indoors, I always use Manual exposure mode. The lighting is usually reasonably consistant and it is easy to make adjustments on the fly. You should also PRE set the White Balance, though the lighting systems at some venues make it impossible since the color temperature varies with the power sine wave. Good Luck and Enjoy your Nikons!