I used to think that my shape was my shape too. It’s not exactly true and it sounds like you have kyphosis.
Neck was bothering me something fierce and I went to see a physical therapist. Long story short is that your shape is largely the results of your muscle strength and your flexibility. And both of these things can be changed rather quickly.
I was 28 when this happened and had been hunched over for as long as I can remember with my mom telling me to stand up straight.
So I got with the guy and he first “mobilized my thoracic spine” a pretty crazy cracking my back operation he did. Then he went into stretching my chest out and strengthening my back. All this time I was wondering when he would fix my neck.
Then we moved on to the fact that when I was lifting weights I was doing lots of chest exercises makng my chest even stronger and hardly ever strengthening my back. It all added up to being way hunched over and then neck pain.
I thought he was full of it but did the exercises anyway, and I’ll be damm if it didn’t work. I was standing straighter, my arms moved out to the side, not just in front, looked better in a suit, all without really trying just doing the exercises and stretches.
I only wich I had known this when I was 14 rather than my mom just whacking me on the back.
I still have to stay on top of it, exercises twice per week and stretches the same same or I go back to where I was. And I’m still not the straightest erect guy around, but I am amazed at how well it worked actually.
So yes, you may have a genetic predisposition to kyphosis but there are some things you can do to fix it.
You may notice if you hang around swimmers much that older swimmers or swimmers from some clubs may still have the hunched over “swimmer’s build” with rounded forward pitched shoulders and hunched backs. But in most clubs the worked has gotten around and they work on it through their dryland training and you won’t see it at all.
As for pressing your buoy, if your head is in the right position then your body will probably be in the right position. I think the total immersion folks have gone this way in the new instructions, not so much the buoy but mostly your head. If you head is low your body will probably be horizontal.