Update:
I spend time today on turning an aperture insert with smaller apertures that screw into the ghost ring aperture. I am still experimenting in regards to the form these screw -inn needs to have. I tried a funnel style screw-in aperture . Will try a square aperture screw-in tomorrow to see what is best.

I did spend time to turn a warthog tusk bead as well, still needs to true the bead and glue it into the 1 mm hole drilled with a hand drill....

Screw insert:

Two different size apertures screw inns:

I did use a piece of warthog tusk to turn a larger front sight bead as well...will experiment with the best suitable bead still....

I filled down an insert to fit into the slot of the island v-express sight that I had to removed when fitted the ghost ring sight: