lateral raises can become close kin to tricep kickbacks....nearly worthless. key is to start where there is already resistance, about 10-20 degrees from hanging at your sides. now watch the pounds go down as you do an actual "no momentum" lateral raise. 2 seconds up....4 seconds down. but for those chasing the number, more power to ya.
I alternate one day I do 10's slow and always with perfect form and the other day I do 15's the same way. I can see a day soon when I could probably use the 20's but I use this excercise for the burn and not trying to lift heavy, I save lifting heavy for bench and squat.