I had not heard of this way to make HST before. I like it. It is similar to the way I make mine. I get 8 HST out of my squares and not on the bias.
I don't have pictures and don't know if I can explain it well but..... I also start with 2 squares of fabric and mark diagonal lines from the corners (my lines would be where this way shows you cut). I sew 1/4" away from the drawn lines. Then I cut along the lines (in an X) and also across both ways (in a +) This gives me 8 HST.
To figure out size - take the finished size wanted and double it then add 2" for seam allowances. 2 x 2 + 2 = 6" squares for 2" finished or 3 x 2 + 2 = 8" squares for 3" finished.
I always make mine this way when I have a lot of HST's to make for a project.