That trick from Parashooter will change the amount of the primary stage of the trigger pull. Since I have never seen a European Krag I am not even sure if they have a 2 stage trigger. It may have been a US thing.
To lighten the pull, I might be inclined to grind the spring thinner. I have a multitude of grinders and wheels that others may not have access to. Be careful not the heat and discolor the spring while grinding, the color will be an indication of heat and may damage the temper.
That said I do not think I would attempt it unless I had a spare in case things went south. A back up possibly could be made from a feeler gauge. I have made one that way for an import revolver.