A few things I did learn:
1) As awesome as the ability to mass process images in camera RAW is, you will have different lighting between images.
2) The masking does get a lot easier as you get use to it. By the end I was flying through masks.
3) Watch Shadows.
4) Layer the images with the closest figure at the top.
I would like to redo this image but I do not have the time right now. I mass processed the images in raw and should have done each individually. Some have dark spots now and some have bright spots. If I can figure out how to copy a mask I should be able to do it within a short amount of time.
I had a lot of fun with this. I was shooting several images and then running back behind the camera and grabbing a new shirt and throwing it on and running back and shooting more. I shot more than I used because I wanted to have different options to chose from. I loaded all of the images into this one image and masked them very roughly. I them stacked the images with the person in the same location and toggled them on and off to pick which one I wanted. For the most part I used the first image I had shot but at least once two of the images overlapped and I had to cut one.