Casual natural fibre dresses for triangle shapes?

[OldLagNewName]

My shoulders are wider than my hips, I have minimal boobage and not much waist (5'8", 12/14). Lots of the dresses I see here are great for curvy people but look rubbish on me (wrap fronts are usually especially bad but things without shaping around the bust also tend to look bad on me). Anyone else a triangle shape and found something that suits them? Just to make it harder, I want natural fibres, or mostly natural.