Solved How to put 3 iPhone videos side by side in one frame

I have 3 separate iPhone video clips. Their frame sizes are: 406x720 360x360 and 406x720 respectively. I would like them to play concurrently side-by-side in a 1280x720 sized frame (16:9 aspect ratio for possible upload to YouTube). I see the combined widths (1172) are a bit shy of the 1280 total frame width but I don't mind a little pillar boxing. How do I do it?
I saw your tutorial on creating a split-screen video with only two videos, but since none of my clips takes up the full screen size of 1280x720, I couldn't see how to adapt that tutorial to what I want to do.

PS - when I play my clips with a a regular media player (I use VLC) the 360x360 clip fills the vertical dimension, I just lose a bit of detail since the resolution is not as good. So it appears all 3 clips will fill the 720 height of the frame.

Hi Jonny

I can't go into extreme detail right now, because I am trying to get some new videos made and uploaded ASAP.
One of these new videos is basically on the topic you are talking about.

You don't need to worry about adding up pixels to equal 1280.
Using Event Pan/Crop and/or Track Motion Tool, you simply Zoom In or Out until you get the videos to fit the space you want them to go.
While you wait for this new tutorial to arrive, I suggest you have a look at these older tutorials.
You should be able to work it out by watching these.

By placing your videos on different video tracks, you can use the Track Motion tool to do what I show in this tutorial.
www.moviestudiozen.com/free-tutorials/sony-movie-studio-platinum/42-how-to-create-a-picture-in-picture-video-in-video-using-sony-vegas-movie-studio-hd-platinum-10

Another related tutorial is this one on creating a Slideshow.
It may seem unrelated, however it will show you how you can pan across a video if needed.
www.moviestudiozen.com/free-tutorials/sony-movie-studio-platinum/63-how-to-create-a-manual-slideshow-using-sony-vegas-movie-studio-hd-platinum-10

Stay tuned for information.
Regards
Derek.