Wait a minute that method leaves you with bias edges.
The best way to make 8 at a time is Eleanor Burns way. For 4 1/2 in HSTs use two squares 10 in. Draw and x and sew 1 /4 in on both sides. Cut block in half both ways then on lines. No bias edges but you will need to square up.
Her triangle square up ruler is a must have and you only make one cut to square up. Fast and accurate.
For 2 1/2 in use 6 in squares, 3 1/2 use 8 in.