Planar defects and microtwins dominate the intermediate temperature creep regime of both Ni- and Co-based superalloys (~700-800C) used for aerospace engines, where diffusion mediated segregation and reordering drive these shearing processes. Local Phase Transformation (LPT) at defects has been shown to prevent rapid damage accumulation by these dominating deformation features by preventing additional passage of partial dislocations in their wake. LPT design has largely focused on η-LPT at superlattice extrinsic stacking faults (SESFs) in Ni-based alloys; a computational framework utilizing high throughput thermodynamic calculations was used which searches composition space with inputs of current alloys and design criteria to optimize formation of LPT, outputting an optimized composition. This is exemplified by creep properties of two Ni-based superalloys, NA1 and NA6. While η-LPT proves useful in crystal orientations promoting SESF/microtwinning, superlattice intrinsic stacking faults (SISFs) leading to deleterious stacking fault ribbons dominate other orientations. The latter may be prevented utilizing χ-LPT and has been shown active in both Ni- and Co-based alloys. Recent studies on RRHT5 have shown that χ-LPT can occur at microtwin interfaces as well, significantly increasing the alloy’s creep strength. Therefore, it is desired to utilize thermodynamically driven design to promote χ-LPT as well, which this work advances. Several alloys are investigated here to determine effects of χ-LPT on creep performance utilizing creep and controlled strain rate testing. Scanning Transmission Electron Microscopy (STEM) is employed for identification of planar defects and LPT, where composition of χ-LPT is determined using atomic resolution energy dispersive x-ray analysis (EDS). Data from characterization efforts will feedback into the alloy design framework such that predictive capabilities are improved for design of new alloys.