I am taking 1 Zinc pill (and 1 Quercetin) right now what is only 6-7 mg of elemental Zinc. Your quote said it is safe up to 40 mg, and I agree, so I could take up to 6 pills without problems.
But I don't want to waste too early the pills (I also plan to give it to others if they can't order it), so yes, I am waiting for the symptoms and then I would take 4-5 pills per day. It seems to work real fast, so I don't have to use too many pills on myself.
I also have lozenges, but they are very low in Zinc. I think sucking on them after being around other people can be beneficial.