I would have to guess that perhaps at most, 1 gram of gold would be needed for a space visor? The process involved in deposition must be considerably more expensive than the actual material involved (a gram of gold is about $44 at today's prices).
(Actually about 300 square feet can be covered by 1 ounce of gold (31.1 grams per troy ounce) I believe; so the amount would be less than 1 gram, but maybe they would waste some, etc. )