I just finished 2 articles for my boss and did use Fusion and no mats. I did a vacuum mount on pieces of matboard and reverse bevel cut around the articles leaving about 1/4" of mat showing and then float mounted these with a foamcore spacer under each to another board.
If you turn the article face down onto a piece of kraft paper, a kraft separator from a box of glass works fine, and place your Fusion on top of the article, and tack it in place. Then put a piece of release paper over this sheet of kraft paper and cook it in your vacuum press for a minute or 2.
Now you take out the paper and carefully trim around the edge of the article with an Exacto knife. Turn it over and remove the piece of kraft paper on the face of the article and you should have an article with a Fusion backing that you can position on any type of backing board and vacuum mount in place without excess Fusion showing around the edges and no reason to use a mat around it.
And using black foamcore instead of white will minimize any ghosting from the reverse side of the newsprint as Paul suggests.
Framerguy