Alot of original rifles just put a trigger in an inlet slot as cross pinned to the stock.
Some metal work fixing coupled with a lock sear and moving part cleanup would make a nice trigger setup.
Not sure where things are in the cva. But getting the sear bar and trigger pin between 1/4 and 1/2 inch is deal for force multiplication of your trigger pull. 1/4 is best.
I like single triggers much better. However, just disassembly, getting the shared edges and rough metal surface cleaned up, a good clean and lube, then reassembly makes older guns seem day and night.