I offset by rotating the arm of the blade toward the offset side. The blade stays perpendicular to the arm so the angle on the blade is from the outside in (so the snow goes down the middle, not off the side). To get an angle, I rotate the blade back the other direction. If I use 15* of offset and 30* of angle, I get 15* of angle from the inside out. I haven't had an issue with the offset pulling the tractor because the snow so far has been light (very cold temps) and only 3-5 inches. I imagine if we get a big, wet snow, I may have some issues.
@Chilly--no way to drill more holes without first trying to weld more plate and then I don't think it would rotate properly (there are guides).
I've had more issues learning to use the loader to push snow to the edge of the parking area and pick up and dump. My second time out was a lot better than the first and the third better than the second.