You will receive many different points of opinion. I would consider the Hunter I-20 ultra rotor. The reason being that you can controll the flow of water at each head plus you will be able to turn off individual heads if need be. However, you will probably need to install the heads closer to the track then 15 ft. You may be fine at 10 ft since the max radius of this model is 47 ft. Understand that since you are trying to achieve uniformed coverage from only one side you will need the radius of your stream to extend past the track. We will need to know more information for spacing suggestions like the available psi and gpm. I hope this helps. I'm interested in hearing some other suggestions because there may be something I didn't think of.