Curious as to what you think is the ideal foresight size and material for your double.
I have two set of barrels by the same maker that measure approximately 0.065". They are easily lost against some backgrounds. The fold-up moon sights are nearly three times that size. I must admit I have used them at times!
I also have a spare foresight for a magazine rifle that states, on the old paper bag it is wrapped in, "fitted with ivory back", however the ivory has gone.