The half-life would be shorter with IV, though I don't know how much. Four administrations of 700 mg will nonetheless remain far superior to two SQ.
The SQ half life I believe is reported as 10 days.
I don't know, and am not certain, if the dose dependency of half-life has been determined. Assuming that half-life is 7 days or more, antibody titers will increase from initial administration through day 21.
Hopefully someone here better knowledge than I has the time to provide more detail.