I would do a search on this and other hunting forums to try to get more information. This site also has a section dedicated to Bighorn Sheep - you might do some research on older posts and see what you find.
It really depends on what kind of hunt you wanna do, The John Day river hunts hold the most sheep in the state. the Desutes has the second, with those hunts its more or less you have to float the rivers to get access, I put in for E. John Day river and plan to float it if i draw the tag. If your looking for more of a mountain hunt look at the Ne Oregon units that hold sheep, good luck in the raffle. keep us posted
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...