These inserts where meant to be used with the original slide assembly removed. The Metalverkin rear sight adapter was placed on m/96's that had been shortened to 1938 ( m/38 ) specifications. There were two types of this military sight used. The type1 sight was graduated from 300m. to 600m. and was calibrated for the m/94 156gr bullet. The type 2 was calibrated for the m/94-41 139gr. projectile. It has graduations from 250m. to 600m.. The rear sight slide, spring and lock has to be removed from the rear sight ladder for these sights to opperate properly. They also have a little screw that can be adjusted up and down to give a correct battle sight zero. You can turn the small screw under the dial to make fine adjustments to "zero" your 250 setting if needed. I think you would have to remove the slider on a standard 96 rear sight to make it work.
If the dial starts at 1 then it's the civilian M96 version. There is a rare tool used with the screw in the center of the wheel to zero the rear sight with. You can make one by filing a screwdriver tip so that it has t**s that will fit the two holes in the screw. You can then adjust the rear sight so that it will be zeroed at 100 meters. You would adjust the sight so that when the wheel is set to 1 your on the money at 100 meters. When set to two it should be close for 200 meters but will likely not be spot on. So what you would do is fiddle with the wheel till it is at the right elevation and then record what the sight setting is in a notebook. You would then do the same for 300, 400, etc. For future use at anything other than 100 yards/meters you would look in your notebook to see where the sight should be set.