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wgscott, thank you for the excellent description of your various parameters. It reinforces some impressions I have: you get what you pay for, though price/performance ratio flattens out at the top of the price range. That doesn't mean paying top dollar is stupid, though, for some.
I've been curious about the GP4000S-II (is that how you spell it?) for a few years now, and I finally saw them at a good price in France at xxcycle.com. I put them on my Lemond (fast handling lightweight racing bike) but the clearance between tire and seat tube was 1mm, and it made me nervous. Too bad. They fit fine on my McLean, steel racing bike with moderate manners. I took one 50-mile hilly ride on it and can't comment yet.
Another impression I have is that the big tire companies who do cutting edge R&D really do produce the best tires. So I don't use WTB, Nashbar, Performance, Maxxis, CST, Kenda tires, and I'm even skeptical of Specialized. The top brands in my mind are Vittoria, Continental, Schwalbe, Panaracer, and Michelin, in no particular order. Each of these companies has one or more specialties and one or more areas they stay out of, but when they try to make the best tire of a particular sub-class, they produce a winner.
Boy am I a tire nut. I could go on all day. Once I was driving a long way with a friend, and I got on the subjects of bike tires and car tires, and my friend in the passenger seat literally fell asleep.
I'd love to try those Compass tires, but it will take some time. First I'll be trying the Voyager Hyper tires on my gravel bike. They've proven great on paved streets. They have a lot of tread wear left.