Fuck man, I didn't think I would need to pull up scholarly sources about foot sweat.
When running, you sweat around 250 grams of sweat per square meter per hour. Variables change +/- 50g ish depending on what you are or are not wearing on the foot, what the ambient temperature is, and what you're doing.
You can work out the maths of your own foot sweat.
Obviously, less physical activity will result in less sweat.