If you have an iPhone, you can use a free level app that will show the angle in degrees. Make sure to zero out the level based the ground. If the ground isn't level, you won't end up getting an accurate reading. Make adjustments in 1 degree increments until you get a comfortable fit. Typically you will need to lower the nose the lower you drop the handlebars, so you don't put too avoid putting too much pressure on the front portion of your pelvis. Make sure you ride in all the different hand positions to make sure it is comfortable.