I believe that folks use various materials for shimming scope mounts in order to compensate for elevation requirements to allow latitude in adjusting of the reticle settings. Celluloid film is generally considered very satisfactory and preferable to adhesive tape, but these days celluloid film is maybe not so readily available.

An extremely satisfactory material that is ideal for the purpose is the fine quality plastic ‘separators’ used in ‘Emporium’ brand cheese slices available In branches of Aldi. It’s non-adhesive and has the integrity once cut to size to provide perfect shims for any adjustment that is necessary....also it happens to be very good cheese... various flavours available! 😎