Yes if you breed him to a hog island you will have some sunsets. However nothing will be "pure hog island" from that breeding. It will be normals, hypos, and sunsets.
I have three 2012 boas. One of my males is at 3 feet ish, eating medium rats. The other two are smaller, at about foot and a half or two feet and eating smalls. They are both from the same breeder though ( one male and one female).
$265 for a pure pair is good, about the going price. Pure hog islands are not to common and often are a percentage of hog island.
Going back to your desired length realize that hog island will grow over 4 feet more than likely. As stated I have a female that was measured at 6 foot but I honestly think is about 7-7 1/2 feet. She is a pure hog island also, no mixing.