Need Advice: I only want to aim with my Right stick

Since we're not given the choice of turning off actions controller sticks will trigger, I want to reduce the effect on my right stick so that it is least likely to trigger anything. Basically, I just want to aim my weapon with my right stick. 

When I'm trying to react quickly to change my aim, I sometimes put a little extra pressure on the stick inadvertently. I try to apply less down pressure as I'm playing. But, sometimes in an effort to change my aim quickly, I will put extra pressure and trigger the assigned action.

I would greatly appreciate anyone who could recommend some settings to reduce triggering actions from when I put "down" pressure on the right stick.

Thanks in advance.