I’m just skipping the second dose. The benefit of the second dose to a young person is almost infinitesimal.
Not getting it saves me time and the discomfort of side effects, and it reserves more doses for others, including eventually other countries. (Yes, we are still very supply constrained when you think globally.)
My impression is that as long as you are outside, that would be sufficient ventilation, and so walking or biking wouldn’t make much difference.
One other factor though could be that if you stand really close to someone, talking loudly could send some bits of saliva over directly, in which case walking and not facing each other would be an improvement.