Don't you need a regular finder? These prism things are heavy and more cumbersome.
It's not unreasonably heavy (the body alone is a handful), and the meter is fairly accurate.
I do have a waist-lever finder hood, ground glass, and Fresnel from another Mamiya (the body was trashed; I salvaged what I could).
I'll see if they will fit.
As I just noted, I just got a C330 Pro body, some lenses, and other accessories at an auction. Might watch this thread for updates.
(I do a lot of reselling. I'm on disability, and reselling brings in some extra money, and I get to put good cameras back into circulation.)