Variation on FlyinPhil's first option.
You can buy a clear helmet safety visor and some mirror window adhesive film.
You will have a decent visor but you may have to hunt down a different coloured film. Most abundant is plain silver. Solution to that is plain old cellophane (that transparent coloured plastic sheets you can get a craft stores). The cellophane will slightly reduce visibility, the more sheets of cellophane you use, the less shapes are definable (tested that personally before applying, one sheet is usually enough to change the colour both externally and internally).