Blueprint help for auto-adjusting image plane to camera fulstrum

I am trying to “attach” a fixed ratio image plane (similar to a camera near/far plane) so that as the FOV changes on the camera, the image plane moves forward/back in relation to the camera it is attached to.

I’ve successfully done this through Motionbuilder, setting the relationship using this formula:

image plane object width (in cm) / 2*Tan(FOV/2).

At an FOV at 38.7, the distance of the plane from camera, along +X, is 680.590027 cm. Both Unreal and Mobu set this relationship correctly.

When I change the FOV in Unreal, however, the relationship breaks and the image plane fails to fill the camera viewport (while still translating to the correct value).

I want to avoid scaling the image plane because at larger FOV number, it will begin to pixelate the attached texture/video.

I am attaching my setup in hopes that someone can point out where I went wrong in my blueprint.

Blueprint Scene with Assets

Quicktime of working solution in Mobu