Tony, I get your point about prep and time management for large gigs. You may note that I said that I will wrap as I pull the 'taters out of the oven/cooker, IF I can time manage it that way. 90% of the time, this is not a problem, and IMHO it results in a much better end product.
As I said, if I can NOT time manage it this way, I coat the spuds with rock salt as I wrap them in foil. Then poke a few fork holes in the foil to allow the moisture to vent as the potatoes cook. The rock salt allows some space for air circulation around the outside of the skin as well as adding a moisture absorbing flavor maker against the skin.
Reality is, as has been pointed out earlier, potatoes held in a properly sized cooler will hold their heat for HOURS. As was also pointed out earlier, lining the bottom of the cooler with towels is a MUST! I also layer a clean dish towel between layers of spuds as I stack them up. In addition to helping with heat retention, doing this allows the towels to absorb some of the moisture that will get trapped inside once the cooler lid is closed.
I'm sure it sounds like I am paranoid about moisture when it comes to baked potatoes. And, in some ways, I suppose I am. The last thing I want to do is to serve a mushy, damp spud to a client or their guest. IMHO, if you are going to serve 'bakers', they should be light and fluffy. A damp potato simply can't achieve this quality.
When You Care Enough to Send the Best