[G6Tanuki]

That PW design is only half-balanced - the L.O. signal's fed to only one of the beam-deflection plates which is distinctly sub-optimal. A proper design feeds L.O. to both plates in anti-phase.

Beam-deflection-mixers can sometimes sound 'deaf' compared to traditional-style radios: that's because in a proper B.D. mixer the internally-generated noise is rather lower than traditional multigrid mixers like 6K8s and ECH35s.

My traditional test is to stick a non-inductive resistor of the same value as the receiver's quoted input-impedance between antenna and earth terminals - then fiddle with the antenna-trim control. If you can get a peak of 'sharsh' from the speaker under these circumstances [where you're essentially listening to the thermal-noise generated by the resistor] then the receiver has adequate sensitivity for use with a real-world antenna.