I find the grid method the quickest and easiest way to sew LOTS of HST. The math is easy to remember as I make my grid squares 1" larger (as opposed to the 7/8 usually recommended) then the size of my unfinished HST then trim them down. So for 4.5" HST you make your grid 5.5" squares. You can get a bunch of HST made quickly with no bias edges and you don't need any special rulers. I have made loads of quilts with HST using this method.