Ease Factors for Aiming Spells

When a magus aims a spell at someone how do you determine the Ease Factor? Does the target get a Defense roll, and if so do shield and weapon bonuses apply? What if the target is an inanimate object? I'm assuming distance plays a part in all this.

The aiming total = Perception + Finesse + Die (stress die if stressful situation, like combat, or simple die otherwise). This generates an attack total.

The target of the spell gets a Defense roll to determine whether the spell "hits" or not. Whether they get a shield and/or weapon defense bonus is situational: you can't use a shield or weapon as a defense against a pit opening up underneath you. Pretty much here you get your dodge as your defense. If it is a rock being dropped on your head, depending upon the size of the rock a shield may come into play, but the weapon would not. If someone conjures a sword and moves it at you to impale you, I would give both shield and weapon as a defense.

There is no general rule. It depends on what you are trying to avoid.

Yes, use your common sense if a weapon or shield can be used against the effect of the spell or not. I think in must cases Dodge should be used.
I see no range modifier in the rules.
In the case of an inanimate object I would use the general ease table. I think aiming a human sized target is 'easy' but it's just me.

Thanks, much appreciated!

Alright.
Got people coming over at noon for our first Ars game ever.
Got the Medieval music mix rolling in Itunes.

Wish me luck.