Allow for two sets of hairstyles to be chosen and swapped between. This will allow you to swap to your shorter hairstyle for those head and body pieces that heavily clip with your longer hairstyle. You can change right back when you equip gear the longer hairstyle does not clip with. The button for it could simply be added next to the "Manually adjust visor" button.

Just like hide/display head piece it would allow you to have the hairstyle set per gear set. No need to change hairstyle because your other class's gear doesn't gel with the hairstyle chosen for your main class's gear.

There are other games which change your hairstyle to a short/long version of it depending on the body piece you wear and whether it would clip severely with it.