"...the old Hornady's manual..." That'll do. The only thing is it has data for Hornady bullets only and limited numbers and types of powders. All bullet maker's books are like that.
"...wanna be on the minimal damage side..." Pick a different bullet. Those are varmint bullets that are made to expand rapidly upon impact with zero regard to saving the hide. Big holes, usually. Check your hunting regs about FMJ bullets if you're hide hunting.
"...a little more power over the 400?..." Magnum primers burn a bit hotter for a bit longer. They're made for igniting hard to light powders and cold weather shooting. Otherwise, you don't need 'em unless your manual says to use 'em. Like Mike says, you're shooting in winter.
"...sure I was compressing the powder..." Compressed loads are nothing to worry about. Some will argue they're more consistent due to the powder being against the primer hole, but that's nonsense. It doesn't matter one way or the other.