Where to place (sub)stacks?

[Beat Cornaz]

I am completing my first commercial standalone and I am unsure of  
where to place the (sub)stacks on the user's machine.

The stack consists of a splash (main stack) with about 30 substacks.  
Some of the substacks display data which is changed by the user and  
needs to be saved.
Now, where do I put my stacks on the users machine? Until now I put  
the whole package (main stack + all substacks) into the Application  
Folder.
But I heard that this might cause problems (i.e. in Vista) because  
some setups do not allow to write to files in the Application Folder.

Is it a good way to place those substacks that need writing to, into  
the Application Support Folder? If so, how do I do that with the  
installer? I got help from Lars Bremer with the Inno Setup Installer,  
which works great, but places all (sub)stacks into the Application  
Folder. How will I solve this?

Are there any other things that I need to be aware of? To be honest,  
I am a tad nervous, as I got into contact with someone who wants to  
distribute my product big. I am not completely done (I found out) and  
he wants to move quick. I did not do extensive testing on different  
systems, just OSX 10.4 and Windows XP 2000.

How will I make an installer for mac OSX?

Thanks a lot for any help.

Beat Cornaz