[i speak in math]

Are you in an area where the lighting is changing rapidly? If so, you could use a semi automatic mode like Av. Then use exposure compensation to raise or lower the light to your liking. If the lighting isn't changing, then take a light reading in spot mode like you want but stay in M mode so you don't need to change settings at all.

Then just get the focus on the subject and shoot away. You don't want to go too shallow on your dof since you have a moving target. I would say f/5.6 - 8 would give good sharpness and dof. However, you may not have the light for that. A good bounced flash or umbrella/softbox would help indoors.