I was taught that your azz should be in the same part of the lane it would be if you were sitting in a car, left of center.
I was out on 234 a few weeks ago, passed part of a line of cars, slid into the space in front of an SUV. Some ijit was there on his bike hugging the right side of the lane.
Couldn't see him till I cleared the SUV and was ducking back into the line. We were both suprised
Hate to think what would have happened if I'd been driving something wider.