Lightmap seams on combined meshes

Hey,

I have a collection of odd shaped spheres combined into 1 mesh (Combined in DCC app not in Unreal). Because its many small spheres, there has to be many UV shells, their meshes are not connected so there’s no sewing them together, and because their odd shaped spheres, they can’t snap to the lightmap grid. There’s no overlaps, but theres hugely obvious seams in the lightmap bake. I wondered if theres any ideas on how to handle this, that doesn’t involve having all the spheres separate. Upping lightmass quality and lowering smoothness down doesn’t help, though raising the lightmap resolution to 1024 does make it far less obvious, but having a crazy high res shadow map isn’t ideal. Any ideas?