Indoor sports are extremely challenging and demanding. I've been shooting upwards of 30 or 40 basketball games every winter for the past several years since all three of my kids play. Just to avoid confusion I must state that I'm a member here because of several Pentax film cameras that I own and love very much but for digital I'm using Sony gear. So I can't really comment on specific matters relating to specific Pentax models etc. But in most high school gyms I have found that even f/2.8 lenses are not fast enough so I use an 85/1.4 and typically stop it down to f/2.2. I set my ISO at 2500 and get shutter speeds between 1/400s and 1/800s. If the gym is really dark I go to f/2. If it is a daytime game with some ambient light I drop the ISO to 1600 and maybe stop down a bit more.
For positioning I stand along the baseline, right about where the 3-point line intersects it. (offensive end of the court)
As mentioned earlier, WB is a tough one. Most gymnasium lighting actually is flashing about 60 times a second and will give you completely different colors at certain points in that cycle. So most commonly some frames will be dark or have a reddish/yellowish tint. You can work on these in PP but it isn't easy. Sometimes I set my WB manually but still get weird results. Some gyms are extremely yellow and absolutely require manual WB settings.
I shoot in RAW and process in LR3 and find that it is just as fast or faster than working with jpegs, and there is a lot more latitude and flexibility.
If you have any interest you can check out a sample of my stuff here:
ASIJ Photo Gallery by revdocjim at pbase.com It was my son's most recent game, and unfortunately they lost badly!