I've done about a million, well, at least a dozen, OBW and SAW blocks. I use a lot of Magic Sizing....hate to wait for startch to dry and then I get flakies and build up on my iron....and I've turned those triangles every way possible and never...knock on wood....had a problem.
TIP....if you are un-deceided on a block layout, shoot a photo of your ''look'' and then move the triangles and shoot again!!! Makes it easy to choose you finished block look
jodi