Good news.. MTG is available at Whole Foods!
They were acquired, but live -on. https://www.ajihealthandnutrition.com/announcing-the-acquisition-of-more-than-gourmet/
Aqueous brines penetrate slowly...like a cm / day at most.
What would the mayo add? I have no idea.
How long do you brine it? What is there to get crunchy...do you flour it?