High back versus thin back PFD and floating position in water?

I’m curious if anyone knows of any research, or videos or anything that might show a comparison of if there is a difference in how you float in the water wearing a high back PFD, versus a full, thinner back PFD?

The easiest comparisons look like they would be some of the NRS models, where they appear to have two models of PFD that have identical fronts, but different back styles, such as the “NRS Raku Fishing PFD” and the “NRS Chinook Fishing PFD”, or the “NRS Odessy PFD” and the “NRS cVest Mesh Back PFD”?

I’m very aware that these are all PFDs and not life jackets, so none of them will roll an unconscious person over in the water or anything like that, but I’m curious of you end up positioned in the water any differently depending on the back style of a PFD? Is your torso likely to be more verticle, or more angled, or anything with one over the other? (Assuming the same person wearing each?)

Just something I’m curious about.

I’ve swum with a bunch of different Class III PFDs, and never felt a difference in how they floated me. Not sure I’ve been in any at the more extreme ends of the design, but suspect iit would be hard to feel a difference.

Aren’t there specs for flotation for a Type III that have to be met regardless of design?

Us fat guys , more belly than chest, the jacket floats up under the arm pits and you float straigh-ish up and down. A submarine line dosent work with skirts.

The higher back makes back of cockpit conflicts less.

I tried leg straps and didn’t care for them. So I DIYed a lower belly band and love it. No more float up when in the water and can be worn lose and easy to snug up quickly when in the water. Made it out of one cam buckle strap and cut some off and sewed up the link out of the leftover piece.