If it scales with weapon, it will state right on the skill.
And sadly, spells don't. The difference in staff and shield is that later on, nearly every wand in the game stop giving points in talents. Staff still give them so if you want more damage and more covery, find a staff of your magic type.
Better to just go wand-shield though. Wand-wand gets high ranged basic and allow for easy combo (like fire wand + poison wand) but with a lot of stronger spells unlocked, you probably won't be using that.
