The problem with messages 1 and 2 is that too many people will not give a shit about other people, and will also assume they can put a mask on correctly. If your goal is to prevent panic buying and hoarding long enough to build an adequate stockpile for medical workers, you probably want to avoid anything that makes those supplies sound superior and valuable.

If I were crafting such a message, I'd say something like this:

"At this time we aren't recommending the use of disposable masks by the general public. For now, those who will be wearing a mask should wear one that's made of tight knit, layered cloth, with a fit that fully encloses the nose and mouth. Cloth masks can be cleaned and reused, and will be easier for most people to wear properly, especially when worn for extended periods of time.

These guidelines reflect our current understanding and will be updated as we learn more."