The principle reason the pilot sits on the left is to aid LOOKOUT and compliance with the Rules of the Air. Some aircraft are designed to be flown from the right, e.g. helicopters and Slingsby military trainers.
If you fly solo and use a seat other than that designed for solo flight, you may not be breaking the law but, if you have an accident, you leave yourself open to charges of endangering the aircraft and other people. Your insurers may forsake you for operating the aircraft in a manner not prescribed in the flight manual; so unless you have a compelling reason to fly it from the right, don't!