  Future searches for new physics beyond the Standard Model are without doubt
in need of a diverse approach and experiments with complementary sensitivities
to different types of classes of models. One of the directions that should be
explored is feebly interacting particles (FIPs) with masses below the
electroweak scale. The interest in FIPs has significantly increased in the last
ten years. Searches for FIPs at colliders have intrinsic limitations in the
region they may probe, significantly restricting exploration of the mass range
$m_{\text{FIP}} < 5-10$\,GeV/c$^2$. Beam dump-like experiments, characterized
by the possibility of extremely high luminosity at relatively high energies and
the effective coverage of the production and decay acceptance, are the perfect
option to generically explore the ``coupling frontier'' of the light FIPs.
Several proposals for beam-dump detectors are currently being considered by
CERN for implementation at the SPS ECN3 beam facility. In this we paper we
analyse in depth how the characteristic geometric parameters of a beam dump
experiment influence the signal yield. We apply an inclusive approach by
considering the phenomenology of different types of FIPs. From the various
production modes and kinematics, we demonstrate that the optimal layout that
maximises the production and decay acceptance consists of a detector located on
the beam-axis, at the shortest possible distance from the target defined by the
systems required to suppress the beam-induced backgrounds.
