I, too, have been exploring the oversized world with both "Wheatsheaves" and the upcoming "Frostfern".
Even petite women can look stunning in oversized garments. Isabel is only 5'2" and weighs under 100 lbs. Brooklyn Tweed's suggestion is to wear an oversized cardigan open so that one's slim figure is revealed underneath. To that, I would add that it helps to choose a design and yarn with good drape.
These two cardigans of mine have 10-12 inches of ease. Admittedly, this makes for a lot of knitting, but I think it's worth the effort!