^^^That's the mod I'm taking about but by the time and money the OP spends modding the SPC he might as well buy the SPL.
However I had this idea about the SPC slippage...drill two holes, put bolts through with nuts holding them down, then drill holes in the corners of each bolt and two sides of the SPC large nut and safety wire it closed. If you torque to at least 150lbs and safety wire, it's going no where.
