I think the answer can be subjective. I have done it with a square as large as 36". I have also done it the entire WOF (after cutting off my needed size like say 24"). I take my 24" x wof by folding one corner of the enlarged strip down to form a triangle and lining up the top edge of my ruler with the fold. I then start cutting my strips.
I do not make continuous binding. For me it is much easier to cut the strips and then sew them together.