Well, there's some differences in the Carmels:
The Carmelites in Spokane are attached pretty tightly to the SSPX, whereas the Carmelites of the Holy Face in Ireland are independent (but closer to the Resistance than SSPX, and were recently endorsed by Archbishop Vigano).
On the other hand, not sure an American postulant could travel to Ireland without first getting the abortion clot shot, so might not be an option.
The Horarium for the Carmelites in Spokane is posted here: https://sspx.org/en/carmelites-spokane
The Horarium for the Carmelites in Ireland is posted here: https://carmelitesholyface.com/horarium
The Irish Carmelites appear to havee the more rigorous schedule of the two, and are more hermitic by design. Some might not be able to handle that (or not desire it).
Generally speaking, there aren't too many considerations for admission: Healthy and no canonical impediments (e.g., debt, marriage, etc.) being the biggest considerations.