All Shoes are a 4-5'' heel, if you are unsure of size please measure the bottom of your foot in centimetres and refer to the measurement guide in the details of the style selected.... you want the length to be just slightly longer than your foot as the plastic will stretch.
For a wider foot, they can be stiff to put on but the plastic stretches as worn so the length is most important.
If you have narrow feet, try using the halter pads which will make the shoe a half size smaller and keep your foot from sliding through the opening, or opt for a style that can use the removable straps... It is common for your toes to come over the front edge of the platform styles.. the pads will help to keep your feet back to tighten up the opening.
*Be aware of your federations rules if there are any*