I have recently dropped an arca 4x5 back while changing orientation, and now have a cracked fresnel/ground glass(gg).

I am not so bothered by it as I found the Arca screen relatively dim, compared to the wista, and was wanting to upgrade at some point in the future.

Could anyone recommend fresnel/screen? It needs to be compatible with the Arca Swiss field 4x5.

Further, I have always been somewhat weary of changing the screen as I do not want to accidentally deregister the back film plane. What is involved in changing the gg+ fresnel and how do I check/ensure the film plane is perfectly aligned with the film within the loaded holder?