I personally like the blonde look a lot. I know you're considering only
spar varnishes, nevertheless, a couple of bits:
When I first redid the brightwork I used Dura-Tuff Clear Coat, not a
spar varnish but a 1-part polyurethane. Got blonde finish that was
indeed tough and durable beyond reasonable expectations. It eventually
went away as the product wasn't available where I was at the time.
Now I use Cetol Natural Teak, without the glossy top coat (also not a
spar varnish), and it also produces a (to me) pleasantly lighter-colored
finish. Not fully blonde, but not what I perceive as the dark, muddy
brown of regular Cetol. It performs as or better than advertised,
although it doesn't stand up to nicks and dings like the Dura-Tuff did.
Phil
s/v Cynosure
Marina Seca work area, San Carlos