  We study strong field ionization of molecular hydrogen in highly intense
co-rotating two-color (CoRTC) laser fields. The measured electron momentum
distributions show alternating half-rings (AHR) that are characteristic for
sub-cycle interference. We report on the role of the two-color field ratio for
the visibility of this sub-cycle interference. The ratio of the peak electric
field at 780 nm compared to the peak electric field at 390 nm $E_{780}/E_{390}$
is varied from 0.037 to 0.18. We find very good agreement with the results from
our semiclassical simulation. We conclude that the AHR pattern is visible if
two conditions are fulfilled. First, the amplitudes of the two pathways that
lead to the sub-cycle interference have to be similar, which is the case for
low two-color field ratios $E_{780}/E_{390}$. Second, the phase difference of
the two pathways must be strong enough to allow for destructive interference,
which is the case for high two-color field ratios $E_{780}/E_{390}$. For
typical experimental conditions, we find that two-color field ratios
$E_{780}/E_{390}$ in the range from 0.037 to 0.12 lead to good visibility of
the AHR pattern. This guides future experiments to measure the Wigner time
delay using holographic angular streaking of electrons (HASE).
