If that one piece plate works, it would me a much better choice than a rear sight replacement plate. I would change your RD, if the pattern does not work, or have a gunsmith/machinist drill and tap the plate for Holosun RD.
Search for a RD dovetail mounting plate that replaces the rear iron sight. Loosing the rail will reduce the height a lot.
I had one made for my Smith & Wesson Model 41 22LR.
I really like to lower window presentation with the Toni inverted mount for my czechmate. I got used to using the racker on the right side, so I left it there.