As an alternative. If you take the Shortcut example I posted in this thread as the basis, it is possible to create one or more sub-routine-esque Shortcuts to retrieve specific fields types.
Whilst perhaps slightly more effort to use for retrieval, it does remove the need for maintaining what is in effect duplicate data in every contact record, which could be a time saving in the long run and avoids situations where the additional duplication & transformation step may not have been carried out.