Precision Reloading might have an answer for you on that. I once asked them about slower steel target loads and they suggested I try WSF and it worked out great in the tests I had them do. I still use it. Good luck. Interesting concept.... which presumes that with regard to reloading at intentionally low pressures (5K to 8K PSI) a fluffier low density flake type powder will be in general more accommodating of such low pressures (as regards maintaining consistent pressures and velocities at various extremes of temperatures) than would be the case for the various of denser ball type powders?