I have a Wenonah Solo Plus that I use solo. The solo seat has two postions one flat, the other canted. With the seat flat my lower back hurts. With it canted my legs ache. Will a backrest likely help in either postion? I would like to eventually kneel, but that doesn't work for me at all. Maybe when I reach a more desirable weight. I weigh 280 now, down from 329! Thanks for any advice on the backrest or seat postion.