Picture of the "graduated" Hoppy Levels

These things are excellent!!!
Look carefully at the pic and you'll see the two aren't identical. They have different curvatures. One for Lengthwise and the other for Crosswise.
Get the coach just-so-exactly-perfectly level then install them IN THE HOUSE but where you can see them from the cockpit. I say HOUSE because a C twists enough that leveling the cab doesn't always level back where you'll be living.
We've had HWH kickdown jacks on the two Class C's we've owned and got to where we leveled with boards after looking at the levels to see where we were close to level as we moved short distances on the site.
Jacks are OK but up on boards is steadier and kickdowns are a PITA.
Unabashed Plug for Sway Bars: Steadier on the site with Sway Bars and resting on the tires than it was without bars and the kickdowns deployed. Not to mention how much better it drives and tracks!