It’s actually the opposite. Special book loads are virtually all lighter loads than starting magnum loads. What you want to avoid is loads so light that there’s so much “sloshing-around” room that the powder ignites inconsistently or sometimes squibs.
For what you are trying to do for moderate loads for your wife, a medium to light bullet (220-240grs) with a medium-weight charge of medium to slightly fast shotgun powder (Unique, Herco, HS-6) or a medium-fast pistol powder (AA#5, W231) will work great.
I personally load 7.5grs W231 with 250gr SWCs for “target/rabbit” loads. For “mouse-fart” loads, I use 44 Special brass with 5.6grs W231 and a 225gr RNFP group-buy bullet from years ago here.