The lateral expansion of thin homoepitaxial cantilevers from mesas has been used to produce areas of on-axis 4H-SiC completely free of dislocations. Cantilever expansion is influenced by the geometric shape and crystallographic orientation of the pregrowth mesa. In order to form larger areas of defect free silicon carbide (SiC), progressive coalescence must occur when adjoining cantilevers merge. The progressive coalescence is largely dictated by the shape and orientation of the pregrowth mesa. We report on refinements to the pregrowth mesa geometry and orientation that allows rapid initiation of cantilever growth and promotes progressive coalescence of merging cantilevers. These modifications to the pregrowth mesa geometry permit larger areas of defect free 4H-SiC to be realized.