Various issues - TIME SENSITIVE

Hello, I'm a novice Obj-C programmer working on an app that needs to be finished by the end of the month. It's far from an ideal situation, but it's my first big break. There are a few roadblocks I cannot get around.

1. I've declared, propertized and synthesized a number of IBOutlet UISwitches in my FirstViewController and saved it. However, when I go to my MainWindow in Interface builder to wire them up, none of them appear. I don't know what to do about that. Is this something unique to the tab bar layout? Because I also made an IBAction for a button, and I was able to wire that up, except the action showed up in FirstResponder, not File's Owner. It works, though, as I tested it with an NSLog.

2. What if you want to display one of two images in an imageView, depending on other circumstances, but the images are of differing dimensions? Can UIImageView support this, and if not, what can?

3. My app will hopefully be able to pass information back and forth between iPhone/iTouch (and perhaps now iPad) units. I was thinking an NSDictionary to hold them. However, users should have the option to include or exclude certain chunks of information if they desire. Can an NSDictionary accommodate this, and if not, what can?

4. I don't have access to an i-Unit, so I have to do as much work and testing on the simulator as I can. There has been a lot of talk about using the mailto: function to create and populate an email for sending. What's the jury's vote on how well and reliably this actually works both on the simulator and the actual unit?