I would also expect that doubling the dose would probably double the spike protein and produce more antibodies (I'd think double or less) It might produce double the side effects too.
Moderna hit me like a load of bricks with flu-like symptoms. I drove my son and a friend to town to get Pfizer and neither one complained about it.
Anecdotal reports from my friends reported the same. I had Moderna and the second dose wiped for out for about three days. I don't know anyone who got the J&J vaccine. Have you heard any reports about any single dose vaccines?
Moderna hit me like a load of bricks with flu-like symptoms. I drove my son and a friend to town to get Pfizer and neither one complained about it.