Wellcome on board.
Was it a Peruvian (Czech) small ring action ? or did you reduce an intermediate length large ring Oberndorf 1909 to a small ring contour ?

The lightening cut I see ,is the thinner left receiver sidewall.

What I miss on a real 33/40 look alike are the lightening cuts on the lower parts on both side of the receiver. (Though a challenge for the stockmaker and not really necessary)

What I dislike is the amount of radius cut on the right side of the receiver ring.

What cartridge have you in mind to choose ?