If you set the vertex group in the Decimate modifier, you can define the hollow density of your lattice. You can also check the triangulate option to keep the result as a triangulated geometry.
If you set the vertex group in the wireframe modifier, you can play with the thickness and control the strength or importance of your paintings. Factor „0“ means 100% importance and therefore zero thickness at the dark blue area. The red area has the same thickness as the one set at the wireframe modifier. Factor „100“ means the painting has zero importance and therefore the whole part has the thickness set in the modifier, no matter the painting.
Finally, adapt the Subdivision Modifier to create smoother connections in the lattice structure. Keep in mind the minimal thickness of the 3D printing process you are using. Always adapt the design to the additive manufacturing technology and used material.