I have a question on user specific settings / preferences for my plugin. I have an time-slot availability booking plugin that allows students to mark their availability for instructor-lead sessions. A simple table showing the weekdays and hours in GMT and allows users to mark their availability times. I would like to give the student the option to select whether they would like to see the slot times in their local time as well. The question is, how can I add a custom field to the user profile and query it before showing the [Local Time] column.
I've reviewed Plugin Field Types and Custom Field API and neither seemed to be the right approach. Also, I would like to keep it clean so if the plugin is uninstalled the custom field is removed as well from users profile.
Any help is greatly appreciated.