Sediment progradation and spreading is a key process during gravity-driven, thin-skinned deformation in salt-bearing passive margins. However, to what degree the size and shape of a progradational sedimentary wedge control gravity-driven deformation is still not clear. We use analogue modelling to compare two endmember configurations constrained by critical wedge theory, in which the sediment wedge has different initial depositional slopes: a 5° critical (stable) slope and a 27° unstable slope. In both configurations, differential loading initiates spreading characterized by a basinward migrating system of linked proximal extension and distal contraction with a translational domain in between. With a critical frontal slope, the translational domain expands as the contractional domain migrates forward with viscous flow evenly distributed. With a steep frontal slope, both extensional and contractional domains migrate at similar rate due to more localized viscous flow under the wedge toe producing diagnostic structures of late extension overprinting early contraction. In both cases, salt flow is dominated by Poiseuille flow with only a subordinate contribution from Couette flow, contrasting to classical gravity gliding systems dominated by Couette flow. Comparison with previous studies reveal similar structural styles and viscous flow patterns. Our study highlights the geometric variations of sedimentary wedges result in variable responses in gravity spreading systems. With a steep frontal slope, the sediment wedge is more likely to collapse and develop spreading associated structures. However, such steep slope systems may not be very common in salt-bearing passive margins as they are less likely to occur in nature.