Don't try to make too much of a change at once. I would try a 90 or 95mm stem first before you go to something much shorter. It will be harder to find a shorter on anyway( I have a 65mm on one of my bikes, it was tough to find). Shortening your cockpit by 25mm is a BIG change.
Also try to get someone to take a picture of you with your hands on the hoods after you adjust your saddle to knee over spindle like the previous poster mentioned. Most people are comfortable with their bodies leaned forward about 45 degrees, and that would be a good position to try to start.