disappointed that Pat sun hoody is too warm as I was looking at that as a possibility. I can tell you can cross off the Ibex Indie for warm sun protection- it's too warm, great mid-layer (or a base layer in very cold weather).
the Merino 1 long sleeve does pretty good in warm, but probably not hot. Mine is a darker color, so maybe a lighter color??
the long sleeve shirt I'm looking at now is the OR Echo- it's UPF rated and only weighs 3.9 oz in a men's large