I would do similar with the spirit level. I recall doing similar many moons ago as kid helping my dad lay paving in the garden.I'm at a point now where I'm feeling a bit overwhelmed and not quite sure how to get the ground level
Good idea to put some stone or sand down down to level it, might need to dig it out a little more so the grids are level to the grass. It doesn't look like there's a massive gradient.
Are the grids hollow, or do they have a solid base? If they're hollow could you wedge/pack them so they're level then add the stone, will it fall through them and fill the void, similar to ballast on railways?

