Sorry for my absence... I was on holiday
I think that the easier way to go may be to build a mechanism in which you could pass a number and the string value is returned. This way, any of the number values could be 'stringified' without adding tags for them all. I am thinking of all of the current string tags that could be removed if this happened.
I realize that this is a departure from the current methodology so I dont really have my hopes up... just an idea.
As for the questions:
What is the actual demand for this type of text time watch? (Potential user base.) Any face where the user would like to see, in text, the number of minutes before the hour.
How many different regional / dialect variants are there? Or, is there an agreed (US) standard for time text-wording? I think it may make sense to start with the simplest as suggested and then assess the value and if it needs to be extended from there.