Just as the title says is it both screws (the left one next to the sim card) and then the one under the water sticker (the sticker one I know for sure)
Generally, yes, adjust both screws. But each Storm can be different. Adjust one, try the click (leaving the phone off, battery still out...just feel the clicking), adjust the other one, feel the click. Then adjust each one a little more and keep feeling the click. Each adjustment should be about a quarter of a turn. Find the click you like.
As Grey said, generally both, but each phone is unique. For mine, I had to adjust both, but each a different amount. I only had do do about 1/8 turn for one and about 1/4 for the other.
