Correcting bCastDynamicShadow warning of instanced static meshes spawned within a blueprint resulting in slow performance?

I have a blueprint with two instanced static meshes in it being modified by another blueprint to create the instances of those instanced static meshes per the instructions in [this post][1] - however the when building the lighting I get the warning:

Large actor receives a pre-shadow and will cause an extreme performance hit unless bCastDynamicShadow is set to false.

along with much slower FPS when running a level with an instance of each of the two blueprints. I’ve tried setting the Mobility on each of the two instanced static meshes to Static however that results in the issue described in the linked post along with shadows like:

These instanced static meshes are going to be walls for a building that won’t be moving around after being created but I would like to be able to initially generate them dynamically rather than placing them all in the level or blueprint by hand. Is there some way to generate them in a way that will get correct shadowing without killing the FPS or is there a different way I should be approaching this problem with the engine for what I’m trying to accomplish?

bCastDynamicShadow and whether a mesh is static or moveable do not affect each other. In this case you would want the mesh set to moveable, but the LightAsIfStatic variable should be on, and the cast dynamic shadows should be off. It only means that lights set to moveable will not cast shadows. your built in lighting should still light your walls normally + beautifully