I followed
THIS tutorial at Oh, Fransson and made 2 boards from 4' x 8' foam insulation boards last summer. I had to cut about 18" off the top to fit as I have a dropped ceiling on this wall - so mine when placed next to each other provide a work space that is 78" high and 96" wide.
I chose not to attach them to the wall so I can move them for taking pictures if need be and because I have really tall trim along my floors so didn't want to lose anymore space. They lean up against the wall just fine. I wish I had done this a long time ago!