I am squinting at the photo - is it actually smocked (elasticated smocking) or are those very small permanent pleats?
As someone who mother nature blessed overabundantly with front upholstery, I would say it depends on where the shaping if it is smocked hits you.
It will look like hell if the front padding sits a little low on the body. I would say this dress demands some of those extremely uplifting underpinnings that are thankfully available for the abundant amongst us these days.
I like Bravissimo for a good in store fitting. Figleaves and brastop have excellent large bras online at decent prices. Simply Be also have a good range and fairly regular discounts.
As for brands, Freya and Panache in my experience keep the shoulder boulders where they are supposed to be.