I don't know about burn speed comparisons, but I know that Lyman's 49th manual lists a load for HS-7 under jacketed 185s. Speer #14 lists loads under 250-gr. LSWCs and 250-gr. jacketed, and also under 260-gr. & 300-gr. jacketed at Ruger-only pressures. Nosler #6 lists HS-7 under 250-gr. jacketed for SAA guns.
All these sources are highly-regarded published, pressure-tested ones, so clearly HS-7 can be put to good use in the 45 LC cartridge. Hopefully, stimpy's PM to you covers some of the particulars.