My 15 y.o sons first bear shot with a 270 win at 40 yds. It has a skull measuered at 20.5 inches. It was so fat we quartered it out and used pack frames to get it out. We were at about 7500 feet in elevation in zone d-4 approx 1.5 miles from camp.
Congrats to your son, I'm still waiting on my first bear. I've had a few chances to get one but I'm being very picky. I want a big bear and all black nose to tail. or a color phase. I dont want a mixed color like brown snout and black hide.
When it comes to scent, there are basically two types; those that attract and those that mask. I've tried both on many occasions. There are lots and lots of "doe in heat" scents, designed to attract a big buck into range. I've also used a "cow in heat" scent while elk hunting.
Another scent would almost be better named as a "coverup smell". The main goal is to cover up human odor or mask it. Though I don't believe you can ever totally eliminate all human...