You’re making huge changes to avoid one of the smaller risks of riding on the road, while introducing entirely new ones. Statistically, you are extremely unlikely to be hit from behind by an automobile while you are driving down the middle of the lane. You are less likely to be hit in the middle of the lane than at the far right. Yes, both do happen, but compared to other forms of car/cyclist collisions, they are not worth making a priority. You should be concentrating on entirely different issues to maximize your safety on the road.