So pleased with the input,
@Manuela and
@BrendaP . This is most helpful.
Yes, the bulk of the dress is underlined, just the sleeves to be left as open lace, so it was the finish on them I needed help with.
As for the hanging before hemming- daft pattern has shoulders so wide it won't stay on a hanger!
I am adding long loops at the armhole to go round the crook of the hanger so once they are on, then I can hang it.
Are these designers not in the same world? make a dress you cannot hang up?
I am going to have a play with that Hong Kong finish, see what I have in stash that looks suitable. I suspect I will end up with the good old French seam for the long sleeve seam, but I may venture into the HK for the armhole... watch this space!