Levelling blocks for camper on driveway with 2 degree grade

You say you don't have a truck.
That means the camper will be resting on the jacks, right?
Why do you need blocks? Use the jacks to level it.

However, it would make sense to put supports under the camper floor to eliminate sway as well as the side loads introduced to the jacks by being parked on a non-level surface. This will take a lot of stress out of the jack mounts.

Edited to add: of course the jacks need to rest on solid, firm ground. You can put pieces of wood underneath to distribute the load.