Oh I've got the coverstitch and it will probably be fine, it's just the fact that I really need a decent piece of the fabric to try out. I'm just hoping that because it is not superfine fabric it will be okay. Best thing I can do is unpick the current coverstitched hem, trim some off and double up the trimmings to try out on that. But yes, you are right
@b15erk, this is why I only sew for myself.
Worst part about is she is a bit of a perfectionist at the best of times, same as DH, but at least if something goes wrong for me I don't have a meltdown. Her daughter in law was there when I picked the dress up and quibbling over the colour of the thread she wanted to give me that she'd bought (one reel). I declined, got plenty of my own, although not many navy, not a colour I like using, it will get a navy thread but I'm not looking for an exact match, who the heck looks down there, plus it has some white flowers on in any case.
At least I've got while next Thursday to do it.