Part 499 above is a common victorian handle in the mokko style
Below are some possible set ups

Cast backplate shown below also a steel version is available.



Note these are just sitting on scanner and not perfectly centered.

This set above is very small , cast backs shown steel backs are 3" wide 559 are 2.25 or 2 & 3/8" wide.
There are endless possibilities as far as handle and backplate mating you can email what you like and I will offer free advice
as to the balance of the set up . You don't want the handle or the backplate to up stage the other . You want an even balance
I will be glad to analyze your set up and or suggest other set ups.