Re: foam dragonfly
Keep in mind that that fly should be fished as a dry not a streamer- sitting fairly still on the surface instead of bine stripped/swung like a minnow.
And I would think mono around 40-50lb would give you big enough eyes. That said, burning mono to make eyes is tricky, stinky, and a bit dangerous. You can buy mono eyes that wapsi sells pretty cheaply.