Michael Daly wrote:

The Kokatat jacket was older and one of the low end models.
The Stolquist was a lot pricier and high end.

Stohlquist is not renowned for high quality at any price.
It's possible they specified a lower grade of latex, or recycled
one of those purplePassion suits (see below).

I've seen the recommendations mostly based on UV protection.

I believe the UV protectiveness of 303 is extremely over-rated.
Many years ago an ad appeared showing two PFDs, one sprayed with 303,
one not. The non-sprayed one was really faded. So I have sprayed
my PFD with 303 over the years, and it still faded badly.

OTOH, before going on low-water rock-infested creekin' runs, I spray
303 on the bottom of my inflatable kayak to make it slide better.

"In general, Latex will decay from salt/sweat."
http://www.purplepassion.com/purple-passion-hints.html

Interesting - I guess I don't have the same hobbies as you :-)

That was just from Google. Try searching "paddling fun" sometime.
Isn't it really bizarre what some people enjoy? I can't see why
anyone would dress up in a latex suit.

Hopefully you also learned something about cervical caps.