  Logic circuits consist of devices that can be controlled between two distinct
states. The recent demonstration that a superconducting current flowing in a
constriction can be controlled via a gate voltage ($V_G$) - can lead to
superconducting logic with better performance than existing logics. However,
before such logic is developed, high reproducibility in the functioning of GCS
devices and optimization of their performance must be achieved. Here, we report
an investigation of gated Nb devices showing GCS with unprecedently-high
reproducibility. Based on the investigation of a statistically-significant
number of devices, we demonstrate that the GCS is independent of the
constriction width, in contrast with previous reports, and confirm a strong
correlation between the GCS and the leakage current ($I_{leak}$) induced by
$V_G$. We also achieve a voltage output in our devices larger than the typical
values reported to date by at least one order of magnitude, which is relevant
for the future interconnection of devices, and show that $I_{leak}$ can be used
as a tool to modulate the operational $V_G$ of devices on a $SiO_2$ substrates.
These results altogether represent an important step forward towards the
optimization of reproducibility and performance of GCS devices, and the future
development of a GCS-based logic.
