Why wouldn't you do both?
I have a macro to switch from my main hand skeletal club to a dagger when I enter stealth. Then my ambush macro restores the mace to the main hand. I see this sort of question a lot and wonder why people just don't do both?
There is an issue if the ambush fails, then you're stuck with your dagger main hand, but I have another macro to just restore the main hand weapon if I miss with the ambush. You could probably tie it back into a sinister strike macro too, which would just restore the main hand weapon if a dagger is equipped in slot 16.
I've been playing around with this for a few days in WSG and it works like a champ. It's not a mod either, just some thing like this:
(macro to enter stealth and equip a weapon main hand, slot 16 is main hand)
/equipslot 16 "Scout's Blade"
/cast Stealth
(emergency restore macro, super complicated)
/equipslot 16 "Skeletal Club"