Your advice is well taken, but, upon looking at stems, it is difficult to determine what length and what rise angle to buy. For example, this one:
Dimension 31.8 Threadless Alloy Stem - 70mm, 31.8mm, 35 Degree, Alloy, Black
My bike has a 54 frame and the head angle is 73. How much will this stem raise the handlebars and how does the stem length affect the equation?