We're planning on parking our new 19 when it arrives (7 days ) on a sloped driveway, nose facing uphill. Anyone out there with a 19' know how far the jack retracts. If the trailer is on a level pad, and the trailer is level, how many more inches will the jack further retract before it completely bottoms (tops??) out? Also, is level either direction affected much by how full the tanks are?