Was searching Home Depot (Rohnert Park, CA) for materials for another project, and in the middle of the concrete and sand stuff saw some 1/2 in thick by 3.5 in wide by 10ft long Homasote strips. Price was $2.79 per strip. Cut a couple to 5ft lengths to fit in car. An easy way to get started with Homasote, especially for shelf layouts.
Still the only place in my area for sheets of Homasote or any extruded foam is one of the lumber yards on Anderson Drive in southern San Rafael - name escapes me.
I will try that angle. The person there said “We don’t have those kinda things is this here store and you will not find a bar like that either” I just looked at him and my wife just cracked up!
I’ve seen strips of homasote like that at a roll paper warehouse I pick up at, they use them in trailers to place the 2000lbs rolls of paper on, I’ve got a small stack of them in my garage but haven’t decided if I will use them yet.