Ah how to wear a proper pant length. Why does this seem to be such a conundrum?
Hems should cover the tops of the feet, toes should be exposed. If your hem back is approx. 1/2 inch from the floor you should look good in a high heeled shoe.
If you are wearing flats or a loafer shoe the hem should hit around the bottom of the ankle.
A boot follows the same theory as heeled shoes try to be 1/2 inch from the floor so that there is not a break in the front of the pants.
A good tailor is a must so find one in your neighborhood that can tailor your pant to the right-length for your shoe and your garment. Each person has a different shape and size and much depends on the pant fabric and the shoe combination.
These are the little things that make such a huge difference in looking and feeling pulled together.