Martini glass centerpieces with feathers

Our daughter had magenta and black ostrich feather centrepieces which I did for her but I made them in tall black ceramic vases which had oasis foam wedged inside to hold the flowers and feathers in place. You can put large feathers in martini vaaes but as you say, this means they will be visible through the glass unless you buy opaque glass vases. They also spread out a lot more in a martini vase because of the shape so they would need to be large, deep V martini vases. By making them in ceramic vases, you will bring the cost down considerably. These were our daughters:-

You could secure a small cube of oasis into the throat of the martini vase with oasis fix which is like very strong plastasine then arrange your feathers and then cover the oasis with coloured gravel or beads which would give a better coverage than the sand. Hope that helps.

Here's how we had ours: