I agree - training for employees has been poor and it's like pulling teeth to use any of the "Perks You Pick". I'm Mosaic 2 and I had to call or chat 3 times to be able to use my "Mint Suite Priority" perk to get the last throne seat on an upcoming EWR-LAX flight. Most agents are clueless "I can't book that seat, it's blocked, maybe it's broken."

To answer your question re Move to Mint - it's explained right here one the website: https://www.jetblue.com/trueblue/perks
I agree it's uncompetitive having to book 96 hours in advance...