Does Pope Francis want Catholics to pray both new prayers at the end of the Rosary or just one or the other? So this question might be rather meaningless in a few months, but I figured I might as well ask here in case someone can parse the Pope's meaning 

The Holy Father said:


  I am also providing two prayers to Our Lady that you can recite at the end of the Rosary, and that I myself will pray in the month of May, in spiritual union with all of you.  I include them with this letter so that they are available to everyone. - Letter on the Month of May - Full text, including prayers


I know lots of times there are prayers that go at the end of some offices where they're "pray this today and that the other day" and they don't give much more guidance.  It just doesn't make much sense to me to add two prayers to the end of a 20 minute mediation, why not just call it one long prayer? 

Anyway, I'm guessing nobody knows the answer to this without asking the Pope, but if there's any similarity to other special prayers, that might answer the question too.
It is obvious by the text that the Holy Father is encouraging the faithful to recite both prayers at the end of the Rosary. However, the pope is simply making this a recommendation in order to help end the pandemic of the covid-19 situation. The faithful may say one or the other, maybe even both of them or neither one at all. 

Some are already praying the Holy Rosary to help end the coronavirus pandemic, without these two suggested prayers of Pope Francis. Some will no doubt continue to do so as that is what they are accustomed to do.

As for myself, I will be making the invocation (3 times) Sancta Corona, ora pro nobis (St. Corona, pray for us) at the end of each decade during the Marian Month of May. St. Corona’s Feast day fall mid way during this month (May 14).

For myself, I prefer something that is simple and neither has to be read or memorized.

Nota Bene: On May 3,2020, Pope Francis asked ‘believers of all religions’ to pray, fast, engage in charitable works on May 14 (Vatican Press Office) which happens to be the feast day of St. Corona! 

Pope Francis never mentioned any connection that the May 14th date was also the feast day of St. Corona.