If you are making a block where you have triangles, rectanges, etc in it, I would suggest that you graph the whole pattern out on paper, using the 6" blocks (which would make the finished size 5.5" in the graph). Then, look at the size of each one, and add your 1/2" seam allowance. On triangles, this is a little tricky I think. I don't use the specialty ruler, and add 7/8" to my finished size. That's why I'm not sure that you would cut them all 1/2" shorter. I would graph to make sure. Hope this helps.
Joyce