  Bell nonclassicality of a single photon superposition in two modes, often
referred to as `nonlocality of a single photon', is one of the most striking
nonclassical phenomena discussed in the context of foundations of quantum
physics. Here we show how to robustly violate local realism within the
weak-field homodyne measurement scheme for \textit{any} superposition of one
photon with vacuum. Our modification of the previously proposed setups involves
tunable beamsplitters at the measurement stations, and the local oscillator
fields significantly varying between the settings, optimally being {\it on} or
{\it off}. As photon number resolving measurements are now feasible, we
advocate for the use of the Clauser-Horne Bell inequalities for detection
events using precisely defined numbers of photons. We find a condition for
optimal measurement settings for the maximal violation of the Clauser-Horne
inequality with weak-field homodyne detection, which states that the
reflectivity of the local beamsplitter must be equal to the strength of the
local oscillator field. We show that this condition holds not only for the
vacuum-one-photon qubit input state, but also for the superposition of a photon
pair with vacuum, which suggests its generality as a property of weak-field
homodyne detection with photon-number resolution. Our findings suggest a
possible path to employ such scenarios in device-independent quantum protocols.
