To my aesthetic sensibility, this is the absolute high-water mark of soft-tops for outlaw speedsters/spyders. Everything you need, nothing you don't.
Some sort of "tent-pole" arrangement for the rear bow, whereby the frame breaks down into pieces that have an elastic cord running through them, so that they needn't be overly long would be ideal. Ideally, the front bow would also be in a couple of pieces, so that the entire arrangement could be stowed in a smallish bag in the frunk.
Side curtains would be strictly optional, as the top wouldn't really amount to anything more than a vague idea.