The limited ionospheric isoplanatic patch will restrict the field of view probably to no more than 3 vs. 10 for the other configurations. If there is no bright source nearby, one's target source is below , or one is observing near the Galactic plane, then one should consider seriously observing simultaneously at 330 MHz. This is because you can fix up your phases using the simultaneously obtained data 330 MHz data. In most cases the 330 MHz data are scientifically complimentary to your 74 MHz data, and so it actually enriches one's data set.
Initial data indicate things get difficult low elevations as well.