I understand the שלטי גיבורים slightly differently.
He seems to say that the Erva section of the head is where you potentially could see the hair attached to the scalp - referring to the entire hairy part of the scalp.
It would seem that he would allow one's bangs and pony-tails to stick out from a Sheitel/Tichel.
Here are the 2 sections you mention:
Once in the middle of that section:
And again in his conclusion:
