Zoom Viewer Design

Hello world. I am quite new to AS3 but I have managed to design something that looks pretty nice, at least for my low level of expertise. Anyhow I would like to share it with all of you so you can give me a hand to improve it.

What I want to achieve with this is that you can easily lay out a few images on the stage, give them instance names and then create a SWF file whose document class is one created with the code that is currently on the time line. Hence making it is easy to create different SWF files that contain different images and behave like they are intended to, using only one piece of code instead of having to include it in each SWF inside the time line.

I am running into many problems as I try to get myself into classes. One of them is that I cannot use instance names in a class, and I would have to add each MovieClip to stage from the class which will terminate my initial purpose of being able to easily lay them out on stage.

One question here: will 100 SWF files that use the same document class take less space than 100 SWF files that have that same code in the time line? Now I am realizing that they might not, in which case going about making a document class for all of them would not really make sense.

Anyhow another issue I had with this is that each time I could be adding a different number of images. The code that I have made uses an array for six MovieClips. If I only add five MovieClips it will give an error because MovieClip number six would not be found. I was wondering if there could be a way of avoiding this problem by saying something like: if MovieClip number six does not exist then dismiss it.

And two last things: would it be possible and worth designing this with OOP, how would you go about it?
Given that every time the images placed on stage will be of different sizes, is there a magic formula for laying things out automatically with AS3?

I am a beginner and there are many questions here but hopefully someone will take the time to answer any of them.

Regards.

Andres