Steve,
Some folks here "rest" ribs for a bit, before eating, but many do not (me included). The only rest I do on ribs is the time it takes to get them from the smoker to the cutting board! There's not enough meat on ribs to benefit from a rest (imo). Large cuts, like butts, briskets, roasts of any kind, definitely benefit from a 1+ hour rest. This is the time when the juice stops coming out of the meat, and is reabsorbed by the meat.
You are correct in the method. A styro cooler, or just a regular plastic cooler, works fine. Double-wrap in foil, and cover with a thick towel to hold the heat better.