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.