I have Thangles and some light weight fabric with the grid printed on it for all sizes.
But I still prefer to make them larger and sq up with the Quilt In A Day triangle square up ruler that you only make one cut to square up.
Also make them 8 at a time with a simple formula: 6 in squares make 2 1/2 in hst, then add 2 in to squares for each size up 8 in squares make 3 1/2 in hst. Draw an x then sew on both sides of line one forth in. Cut in half both ways them on lines to make 8 hst.