FX Impact Trigger Adjustment

Ok, Ive reviewed E. Rowes video on adjusting the trigger on an Impact and read the owners manual. Im still unclear about how to make my second stage a bit lighter. Im ok with the first stage travel and the trigger returns when I DO NOT make the shot. All I want to do is slightly lessen the finger pressure it takes to fire the second stage. Also, will doing any trigger adjustments void the warranty?