<p>This work investigates the influence of geometrical configuration and mechanical contact efficiency on the thermal performance of cryogenic heat switches. A simulation framework was developed to model heat transfer across copper stainless-steel assemblies, incorporating thermal contraction, enthalpy evolution, and thermal contact resistance representing the quality of surface contact between the conductors. The results show that both the conductor length ratio and thermal contact resistance strongly affect the disconnection temperature. When the thermal contact resistance approaches unity, the switch behaviour becomes largely independent of geometry, whereas high thermal contact resistance values amplify the effect of conductor ratio and mechanical misalignment. Experimental tests performed on prototype switches confirmed these trends qualitatively, revealing a pronounced temperature lag between the hot and cold ends, consistent with reduced interfacial conductivity. The introduction of a negative gap was found to further lower the disconnection temperature in all cases. Based on these findings, design improvements such as implementing a conical interface are proposed to enhance alignment, increase reduce the thermal contact resistance, and achieve more reproducible switching characteristics.</p>