So just to report back, I decided to contact the Amex platinum concierge, which I've hardly used even though I've had the card for almost 10 years. They have booked us on a full day (8 hour) private tour with luxury transport (picking us up directly from our Airbnb), and we will be working directly with the tour provider to customize our day. We are not going until March but I will report back on this option. Amex listened to what I wanted and emailed us 5 or 6 different tour options, with options for group or private tours for each. they did not seem generic, but well curated, including a "hipster tour" of La Roma and a walking food market tour. We may add one of those on another day, but guess that the 8 hour tour will be enough.

The company they connected us with is Style Walk MX, which is very well reviewed on Trip Advisor (https://www.tripadvisor.com/Attracti...ulf_Coast.html). The prices that Amex offered were the same as the prices published online for the company. I'm glad to have taken advantage of this benefit, and hopefully I will still feel that way after the tour. Concierge also offered to make dinner reservations, but I had already taken care of that myself.