Dear friend:
The Sportster was my first experience with Flitetest, for this reason I chose the FT kit . I used for building the plane the same technics and materials as showed in the Josh's video. I thing it's the better way to building this model. A small improvement to finishing the model, before painting, was to use a double side tape with the paper skin of foam board in some edges or corners.
For painting the model I used paint spray cans from Montana Colors , they are used for the urban artists.
http://www.montanacolors.com/webapp/spray?id=58
You should practise the painting of model with the scrap pieces of foam board for best finishes. There is a video in FT web page for painting models with spray cans.