Bejazzled, I'd say for both it's the material, the type and the weight. Both are things that hang off your body so they need a sculptural shape of their own. The coat has the added demand of how it's cut, body type comes into it a bit but unless you're really on the extreme ends of a body shape (that's not weight related, it's proportion related) but it's the ability of the material to hold the shape rather than your body being the scaffolding to the construction of the coat.
Methenyouplus4, probably not that unfamiliar. However, what I'd advise changing first is your thinking around it. You've got a great height and large shoulders are not a bad feature to have at all. It's very statuesque and a bit of natural grace not to be taken for granted. Whilst the French approach to style has its more undesirable points one of the best things about it, I feel, is to stop seeing things as flaws. They work with the texture of their hair not against it, they don't try to conjure boobs out of nothing with push up bras and what have you, it's really about embracing your best parts and not hiding or covering up (which usually just ends up emphasising it more) what you perceive to be a flaw and accepting it for what it is, simply another part of you.
I remember being a bit shocked by Caroline de Maigret in an interview commenting that she was always blessed in the looks department in a way that wasn't self-deprecating or boasting, just an assessment. She is most definitely beautiful but it's not a conventional beauty and one most women would have to learn to come to appreciate with age. Had she grown up anywhere else I doubt she'd be so positive about her own looks from the onset.
I'm guessing where you struggle is much more with how to work the proportions of it all and the shoulders stick out noticeably as a result but going by your measurements I can't imagine them to be that big. I assume you've been bra intervened already, though would hazzard a guess that you struggle more with finding a good bra style rather than the right size.
What body shape do you think you are? By my estimation you're actually a tall altered hourglass whose volume in the breasts has decided to take residency in your lower abdomen instead. Are the tips of your shoulder roughly around where the hip bones stick out to? You're definitely in hourglass territory then, most people confuse it for a bust waist hips measurement but it's actually a ratio of shoulders to waist and hips to waist, the bust only plays into it marginally. To test my theory you'd be dressing in the vertical to emphasise length and though I mostly I hate the emphasise your waist anthem in your case acknowledging it will be important since it isn't as naturally shaped as it used to be, but you don't have to dress around it. If you can grab a man's shirt get one of those, and flip up the collar (women's blouses and shirts don't tend to want to stay up). If he's got a tuxedo belt hiddden in the back of the closet, steal that too. Otherwise, fashion a large scarf into an obi-style belt. Get your highest waist fitting pants and wrap the belt atop it near your natural waist (just above the belly button on most), tie it with a slimmer waist belt atop it if necessary. Stick on heels for full effect.
Garance Dore is probably very similar in build, she's less Parisian in a way, definitely a more regular size by French standards (I'd say she's at least a 10 or 12 but hard to judge really) and tall. I gave up on her blog a long time ago as it has become more of a digital platform but she still dresses with a great sense of style. She'll always be adding length at the neck drawing the eye vertical, in a blazer she'll look for softer edges around the collar but the shoulders will be sharp (but equally on blazers and coats you can pull the collars up), and if she can't create height in the garment itself she'll stick a bun on her head instead.
I think your other challenge will be that the type of clothes that suit you best simply aren't in fashion currently. That's wide flowing trousers with a large band and a side zipper (they flatter better because they hang at the highest point of your hips but because there's no tension on the zipper in the middle they drop, creating a V shape, again emphasising a vertical line rather than cutting you in half, a voluminous pair of pants with a zipper at the front will instead just add more bulk), halter neck tops, sleeveless turtlenecks, and racerback tops. They sound terrible for broad shoulders, but rather they make them work in a way that brings out their beauty. Forget the Breton top or horizontal stripes, instead, go for vertical ones.