Mr. Sloan pretty much designed the cartridge around the 300 gr. SMK, but that's not to say that others wouldn't work. He told me he has best results loading them just touching the lands. MVs were stated as 2700 "and change" (i.e. low 2700s) as the sweet spot. I also seem to remember him saying that MVs with H1000 usually were around 100 fps lower than with other similar powders like Retumbo, Ramshot Magnum, etc. That would seem to be a little at odds with what you found in your search, though.