Sloped driveway grade needed for safely backing / storing our 38fdds.

[Hangar11]

after 4 great years of seasonal camping in our jayco jayflight 38fdds. We are thinking about some travel time with it.
Which means we keep it at home....So prep and departure i& return is ez.
our seasonal is 3+ hours away so it's really not practical making it out departure point.

We have the towing part set. Dodge ram.....etc.....

parking at home.... we need to back it up a hill.... and currently the ground clearance is 6+ inches short. rear bumper hits , yeah tried the boards under the wheels got it parked but looking for the ez button....

Is there a " standard " grade that tt are built to so we can regrade and know this unit and others we may buy will easily park along side our home ???

thank you I advance for comment....
safe camping......
BB