Spline Remesh Modifier for UE 5.8 Mesh Landscape

Does anyone have any experience with the Spline Remesh Modifier?

I have Spline modifiers workin on my landscape mesh, but I want to increase the resolution where the spline goes to avoid sawtoothing into the lower resolution base mesh.

The regular Remesh modifier works like I expect, but it’s rectangular and does will remesh a much larger area than what I want.

The big problems I have is when I drag the Spline Remesh Modifier into the scene, and go to select the spline to reference, there is no information in the dropdown, and it can’t find any splines. Also the Reference Actor fields are greyed out, including the eyedropper. The Component Name field is greyed out as well.

I haven’t been able to find any information on anyone using this modifier yet, and the documentation doesn’t include how to select the spline. Does anyone have any information, or any experience with getting it to work?

Thanks