Sorry to hear about the 'cat's' Roger. They certainly make things more than difficult. Good thing they can be corrected with new lenses.(that's the fix up here)
If switching to this style of sighting, make the rear sight high, so it can be filed to the correct height at the range while shooting. This is the easiest method, as getting the front sight height correct for the rear is more dificult than getting the rear correct for the front.
Here's the front sight on the .69 cal. rifle.
Here's another bead, for a higher express-type sight.
Here's the front sight off a friend's 'Sporting' Rifle.
Here's a drawing showing angles, height and base for a Sporting Rifle's front sight. It is applicable to a longrifle as well. Forsyth noted the front sight should be 1/2" long, for strength. Most I've seen are about 4/10". Normal 1/8" diameter round brass rod is a good one for this. Once soldered to the base, it is easily filed to a tapered shape, then the 'nose' can easily be reduced to whatever size looks good to you.
Note the angle of the bead - it has sharp sides, yet a sloping 'face'. This ensures that light reflection is 'true', always a circle of light without highlights & doesn't cause the off shots, as a rounded edge on a bead or blade will.