Shape and weight (within reason) aren't as important as bullet size. Make it fit the throat of that Krag (.0005" undersize), get the hang of the trigger, squint your eyes just right, and you'll be eating for free.

Krag throat dimensions are all over the map. It's wise to measure same and size accordingly.

Perhaps a Lyman 17A in the ramp dovetail would solve the front sight height issue and provide the aperture that you like, Brent?