Could you share the link or shop where I can purchase the neoprene neck seal? I would like to try it out.
Neoprene Neckseal
It is warmer on the surface... the deeper you go the more it is compressed - so the same as latex at depth.
It does compress, but I think it is not right at all to say that at depth it is the same as latex. Even one layer of the neoprene will always be thicker than latex, at any depth. And, for the width of the doubled-over part, you have double the thickness providing insulation. And below the doubled-over area, you have some air between the neoprene and your neck.
Also, you talked about it like you wouldn't use a neo neck seal because you might have to have a buddy help you get it tucked in. I have to ask, so? Why is that a problem?
I have gotten various people to help me with mine. I don't see that as a big deal. Definitely not a reason that I would use latex or silicone instead. The only problem would be if I were diving solo, with nobody else around at all. That is rare. And, I can usually fix my neck seal myself anyway. It's only when I have on my thickest undies that it becomes difficult to tuck the back part and make sure it's right.
I have never used seal-on-seal dry gloves. I don't think I ever would. If I don't want the bulk of rings, I use wet gloves. If the water is too cold for wet gloves AND I can't do what I need to do with the bulk of dry glove rings, then I'm not sure what I would do. It hasn't happened to me yet.