The pellon is about 1/8 inch thick but has a tight "weave" IMHO. I don't think it's puffy at all, but that is also subjective.
I haven't heard of the Bosal before, where did you find it?
BUT I really like the Pellon. It isn't puffy, but it does help with the shape. There is a stiffer pellon that you can find at Walmart, but i can't remember the number. It is denser than the 987.