When we first got our current MH, I parked on our very slightly downhill (to the street) driveway, put the biggest bubble level I could fit into the bottom of the fridge, then juggled the jacking system to get level in both axes.
I then stuck two of the self-adhesive levels where I could easily see them from the driver's seat, getting their bubbles spot on. Levelling at a CG is easy now, unless the site is seriously off level. At daughter's house, we need blocks under the front jacks because of the driveway slope.
We're having a new fridge installed, so when we get the rig home from the repair place, I'll recheck.