the assembly manual says to have the rear axle 5" away from the frame to tighten the controll arms.Without removing the springs i can only get it to around 10" from frame.Do I need to remove the springs or is it ok to torque them with just the weight of the car on the suspension?

I think 10 inches was all I could get too. I even used ratchet straps to pull it down. I just tightened it at 10.

Ive only ever tightened them down with the suspension at ride height. Never have had a problem. Use some loctite if you're worried about the nuts backing off.