sounds like you have this figured out already. But I just a couple of weeks ago (where???) saw a tute that said to be sure to press open each seamed "corner" of those HST and then to open and make sure to use the iron point to press on the straight of grain. Said to Not use the side of the iron to open the seam and press (what I'd been doing) cause it's on the bias and can distort the seam with a curve instead. Makes perfect sense and works, too!