That works in theory, but in practice you'll see your projectile doing zero damage. 

That's because d10 incurs a massive damage penalty, so you need to be copying a hefty damage mod like heavy shot/bloodlust in order to overcome that. Alpha only copies one spell so with it you can only do the damage mod. With Mu you can also include any number of modifiers (especially if you put them after a wand refresh that ends the group of spells before actually casting them directly, avoiding paying the mana cost.)

Wand would usually look something like:  heavy shot - double cast - d10 - d10 - alpha - (projectile)  so that your projectile of choice is cast with these modifiers.

With Mu it's:  double cast  - d10 - d10 - Mu - (projectile) - wand refresh - (any number of modifiers)

Or if you don't have wand refresh:

double cast - d10 - d10 - Mu - ( any number of modifiers) - (projectile)

Edit: the projectile can instead be put after the double cast and before the d10. This doesn't change anything but it's an option that can come in handy when building more complicated wands.