You need an (approx) 9mm blade
I know k98s are supposed to be zeroed at 100 meters, but we haven't got the original ammo and can't always shoot at 100 meters or above. You should be able to get a 9mm blade somewhere - they are catalog items here, because most military Mausers were zeroed at 200-300 meters, according to type and country, so this is a standard problem - and that will give you room for adjustment. It is worth while getting it right at 50 meters/yards first, otherwise you may well be completely off the target at 100.
Just one thought: are you using a 6 o'clock hold? (You should be).
If you do, and adjust your sights so the POI is centered at 50 with the typical ISSF pistol target, with an 8-inch black, then when you move the target back to 100 you are in fact lifting the sight a bit relative to the center, because the reduction in apparent size of the black means that the bottom of the black now appears higher. This helps to compensate for the extra drop, so you should still be well in the black at 100.
Patrick