If you're thinking about reduced power loads in your .45-70 you really ought to consider Trail Boss. Unlike pistol powders, TB is very bulky and 12 gr will do a very good job of filling the massive case. More consistant ignition and groupings will result. I've loaded around 100 or so using 14 gr and 300-350 gr cast bullets and found the recoil to be very mild. I can't imagine 405's being much different.
Just my two cents.