Ok, so I have been talking it over with my GM and I wanted to throw this out to you as well because as I understand it this will save me a lot of drain in the future. I was looking over improved invisiblity vs regular invis. The regular kind if like obfuscate from WOD. People viewing the person actually see them it is only a mental filter that prevents them from registering the fact they see the invisible person. So they get a resistance test to overcome the spell and actually see the enchanted person.

Improved invisiblity however does actually turn the person invisible bending light around the subject so the average viewer gets no roll to resist improved invisibility. So unless I am missunderstanding the rules if you have improved invisiblity you don't need to cast it at a very high force at all. 1 or 2 would be fine. After all, if you have someone dispelling the force 2 spell that's just one round your now-visible street-sam has to shoot them in the head 6 times. So save yourself some drain, get improved invisiblity and not regular invisiblity then use it at force 2.

(Unless you are making yourself invisible then cast at regular force for the most hits possible... After all.. that street sam can be replaced but you are very important to you.)

I ignore the bending of light while using Improved Invisibility. Bending light would make the spell a Manipulation and not an Illusion. Thus, Improved Invisibility can then be resisted as per normal: either a threshold test vs. the object resistance or by using willpower and counterspelling.

Improved Invisibility is still resisted, and the force sets the cap for your hits (not net hits). If you cap it at Force 2 you won't be able to overcome the object resistance for most things that would be looking at you.

If we consider your concept true, and say that Improved Invisibilty is bending light around the "target" - then the cast would need to overcome the Threshold of the "target". A runner in all his gear would be highly processed material, requiring a Threshold of 3 or 4 and thus a Focre of 3 or 4. A naked person we could argue would only need a Force 1.

Nekkid ninja physad assaults, that's all I need in my game...

My understanding is that the Object Resistance that gets used is that of what the spell is screwing with. Since what you're screwing with when you use Improved Invisibility is cameras and the like, my read is that you should be using the Object Resistance of the camera.