The simplest solution is to do nothing. It’s not necessary for sites to look pixel perfect in every browser.
This is especially true of a single pixel difference. Even if the user actually uses two browsers to view the site it’s still highly unlikely that they will notice a single pixel.
Additionally, are you proposing to embed the font (assuming the licence will permit)? If not then the default font wont be the same in every browser.
Finally, I generally don’t use top / bottom padding in li or a elements as I can use line-height to set their heights equal to the ul.