Along the nice authentic manual of HS129, there is also a great book to read about HS129. It is 'HS129 Panzerjager!' by Martin Pegg published from Classic Publications.
In the Page 50, I found some useful information on the gunsight & vanes.
'This consisted of a Revi C12/C or C12/D sight, on the side of which was mounted a crude form of bombsight comprising four horizontal vanes with vertical wires passing through them. Release heights of 10, 50, 100 or 200m(33, 164, 328, 656 ft) were marked on the vanes and the pilot aimed his bombs by aligning the target with the particular vane appropriate for release altitude.'
That's all and there is no related picture or description with it. So it's a bit confusing. Which vane is for 10m? Is that top for 10m or the bottom one is for 10m? Well I don't know.
