My wife is from there, she grew up in Frolona. Info I've gathered from folks, my father in law included, who've hunted the area since youth is that week after Thanksgiving through first week of December is best.
That is simply their observations & opinions. Nothing scientific by any means.
I've hunted Heard my whole life and agree the map is off by quite a few weeks. I'd say the 21st of November if we get a really cold snap into the first week of December are prime.